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This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Chewing a food is a chemical or physical change ? |
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Answer» Answer: Explanation: The process of digestion INVOLVES a series of chemical and physical changes to food substances. When we put food into our mouths and chew it, it is broken down into SMALLER pieces for easier digestion by the STOMACH. This is a physical CHANGE. ... Sometimes, we can taste this chemical REACTION as it occurs. |
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| 2. |
if the activation energy of a reaction is 80.9 × 10^3 j/mol . calculate the fraction of molecules at 427°C , which have enough energy to react to form the products |
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Answer» if the activation energy of a reaction is 80.9 × 10^3 j/mol . CALCULATE the FRACTION of molecules at 427°C , which have enough energy to react to form the products solution : according to Arrhenius's activation energy FORMULA, where A is fraction of molecules which have enough energy to react to form of the product, Ea is activation energy and T is TEMPERATURE in Kelvin. here, T = 427°C = 427 + 273 = 700K Ea = 80.9 × 10³ = 80900 J/mol and R = 25/3 J/mol.K now, A = = = 9.48390025e-7 ≈ 9.5 × 10^-7 hence, 9.5 × 10^-7 is the answer. |
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| 3. |
Plaster of Paris should be stored in moisture-proof container.explain why? |
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Answer» Answer: PLASTER of PARIS in contact with moisture (water) CHANGES to solid hard mass, gypsum. THEREFORE, it GETS wasted. Hence it should be stored in moisture proof containers. please make this answer as brainlist please |
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| 4. |
SUMIIVER ASSIGNMENT1. Chemistry3. Whatterswem alicutAs meer pressure on the walls of the5. Comer the following temperatatercoles seen on the puresure on the walls of the container Assign teasonthe following temperature to keiver Scale ta 100 100is man by density? 7 Gree themeore me characteristic of the particles siteles seen on the outer surface of a zase containing set water suof gaseous state directly to solid state without going througriauto sanesis a surface phenomenon.e** bere atent heat of vaporizationin w temperature remain constant during the change of state of any song?3 Dee Sublimation with examples4. Do sweat more on a dry day or humid day? justify your reason25 w do we see water droplets on the outer surface of a glass containing c old water36. Conuer the following temperature to the CELCIUS scale la 25K 373%.properties that ouids have in common with solidssoperties that guids have in common with gases5. Whi agoen to the melting point temperature of ice if some common satt sadded toou show that it has maximum compressibility?2. Physicsto go to a place by a vehicle. Take readings of odometer and speedometer atter eenwordestination Record these observations in tabular form, plot graphs between stamm enSanelesne this tation is uniform or non-uniform.the acceleration of a body moving with uniform velocity?does the stope or distance-time graph gives?en bezeroeven when distance is not zero? Give Example. |
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Answer» Answer: i couldn't UNDERSTAND a WORD of what u SAID. provide the DETAILS |
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| 5. |
Freezing point of 0.1 molar solution of nh4cl is found to be 0.324 |
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Answer» Explanation: · NH4Cl is a salt of WEAK base NH4OH and strong ACID HCl. We NEED to have the value of Kb (base dissociation constant) of 0.01 M NH4OH for the calculation of the pH of 0.01 M NH4Cl. ... What is the pH of the solution obtained by mixing 5ml of 0.1M NH4OH with 250ml of 0.1M NH4CL? |
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| 6. |
Explain the reactivity and relative strength of c- halogen bond in alkyl, allyl, benzyl, vinyl and arylhalides. |
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Answer» The first of these is covalent bond STRENGTH. The strongest of the carbon-halogen covalent bonds is that to FLUORINE. Remarkably, this is the strongest COMMON single bond to carbon, being roughly 30 kcal/mole stronger than a carbon-carbon bond and about 15 kcal/mole stronger than a carbon-hydrogen bond |
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| 7. |
Experiment shows that nickel oxide has the formula ni o 0.96 1.00 . What fraction of nickel exists as of ni2+ and ni3+ ions? |
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Answer» Explanation: What fractions of NICKEL EXIST as NI2+ and Ni3+ ions. ... Question 16 Analysis shows that nickel oxide has the formula Ni0.98O1.00 |
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| 8. |
12. Explain why temperature remain constant du13. Define Sublimation with examples.14. Do we sweat more on a dry day or humid day15. Why do we see water droplets on the outers16. Convert the following temperature to the CE17. Ust two properties that liquids have in comm18 Ust two properties that liquids have in comm19. What will happen to the melting point tempeanswer20. How will you show that air has maximum con |
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Answer» Answer: 13 the matter can change SOLID to gas without liquid ex=Burn the TYRE |
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| 9. |
The ratio of wavelength of Frist line of Lyman series in Li+2andin deuterium is |
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Answer» Answer: |
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| 10. |
The molecules in the gas are in constant motion true or false |
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Answer» Yes, it's true, that the molecules in the gas are in constant RANDOM motion and frequently COLLIDE with each other and with the walls of any CONTAINER. Hope it HELPS you mate!! |
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| 11. |
Write the equation of tert.butyl Bromide reacts with mg metal in the presence of dry ether. |
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Answer» okghhvccccxxccvvhjj |
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| 12. |
unscramble the jumbled words given below related to synthetic materials. (a) anory (b) lopmery (c) relyteen (d) laspict(e)yespolter(f)felyon |
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Answer» a) rayon b) polymer c) terylene d) plastic e) polyester f) teflon Hope it HELPS.. REGARDS:) |
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| 13. |
Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11,7 and 9, respectively, classify the solutions as given below.(AS)(a) neutral (b) strongly alkaline (c) strongly acidic (d) weakly acidic (e) weakly alkaline |
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Answer» Answer: a). D b). C c). B d). A E). E |
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| 14. |
) Derive an expression for the Beer-Lambert law. |
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Answer» Explanation: The Beer-Lambert LAW states that the QUANTITY of light ABSORBED by a substance dissolved in a fully transmitting solvent is directly proportional to the concentration of the substance and the path length of the light through the solution. |
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| 15. |
Rohan dropped a crystal of copper sulphate in 2 beaker A and B containing cold and hot water respectively. In which beaker dissolution will be fast and why? |
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Answer» Answer: The crystals of copper sulphate will dissolve FASTER in the hot WATER. Explanation: this is because in the hot water the molecules have higher kinetic energy and so the molecules in the hot water MOVES RAPIDLY. |
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| 16. |
an atomic compound on analysis is found to have the following composition c=41.4%,h=5.75%, n=16.08% are rest is oxygen. Find out the empirical formula of the compound. |
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Answer» C3H4NO4 Explanation: GIVEN in the pic Find no. Of MOLES for each Divide other MOLE nos. By the smallest one Get RESPECTIVE nos. For each element |
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| 17. |
when a copper wire was left in silver nitrate solution for sometime it was observed that the solution turns bluish green first part explain the observation second part write the balance chemical equation to represent the change taking place |
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Answer» the copper displaces silver Explanation: Copper metal DISSOLVES in a silver nitrate solution. The BALANCED equation for the reaction is: Cu(s) + 2AgNO3(aq) -------> Cu(NO3)2(aq) + 2Ag(s). PLZ mark it BRAINLIEST |
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| 18. |
Which of the following gases can be used for storage of fresh sample of an oil for a long time???1. Co2 and O22. nitrogen or oxygen3. Co2 or He4. He or nitrogen |
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Answer» Answer: 4. He or N Explanation: Both of these GASES are unreactive and can STORE oil without DAMAGING it. |
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| 19. |
How to identify that it is a solute or solvent in an given question |
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Answer» Explanation:SOLUTE is present always in lesser quantity and SOLVENT is present in HIGHER quantity |
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| 20. |
Hi guysplease tell me, why is solution not heated to dryness to get crystals ? |
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Answer» Explanation: WATER was removed by heating solution until with the more SATURATED solution is formed. for pure crystal and filter . please mark has BRAINLIST. freind |
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| 21. |
A)write the chemical formal oh hydrogen copper sulphate and anhydrous copper sulphate. giving an activity to illustrate how these two are inter convertible.b)write chemical name and formulae of plaster of paris and gypsum. |
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Answer» FORMULA of COPPER SULPHATE is CUSO ⁴ |
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| 22. |
Ethene gas is bubbled through the water saturated with chlorine |
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Answer» do you WANT the RESULT of this EXPERIMENT or..... what is the QUESTION, ACTUALLY |
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| 23. |
Equation whensilver chloride is exposed to sunlight |
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Answer» Answer: when silver CHLORIDE is exposed to SUNLIGHT FOLLOWING reaction OCCUR : 2AgCl = 2Ag+ CL2 |
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| 24. |
Calculate the freezing point and boiling point of a solution containing 17.4 g of naphthalene |
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Answer» CONSIDER 1.60 G of naphthalene (C10H8) is DISSOLVED in 20.0 g of BENZENE. The freezing point of benzene is 5.5oC, and the freezing point of the mixture is 2.8oC |
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| 25. |
What this process called |
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Answer» onion PEEL EXPERIMENT for SEEING cells |
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| 26. |
In the double displacement reaction between aqueous potassium iodide and aqueous lead nitrate a yellow precipitate of lead iodide is formed. while performing the activity if lead lead nitrate is not available which of the following can be used in place of lead nitrate???1.lead sulphate (insoluble)2.lead acetate3.ammonium nitrate4.potassium sulphate |
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Answer» Lead sulphate can be USED because Lead will again remain PRECIPITATE as potassium will REPLACE lead |
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| 27. |
I need this answer ASAP please |
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| 29. |
Calculate the volume of air containing 21% oxygen by volume at STP, required in order to convert 294cm³ of sulphur dioxide to sulphur trioxide under the same conditions(FIITJEE Question). |
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Answer» Answer: The volume of the AIR with 21 % oxygen required to to convert 294cm³ of sulphur dioxide to sulphur trioxide is 700cm³ Explanation: The equation of the reaction of sulphur dioxide ( SO₂) and Oxygen (O₂) to form sulphur trioxide ( SO₃), is given below: 2SO₂ (G) + O₂ (g) ⇒ 2SO₃ (g) We can calculate the moles of SO₂ and use it to find the moles of O₂ required by using the equation We have 294 cm³ of SO₂, we can calculate the moles of the SO₂ by use of Avagadro's LAW Avagadros law state that 1 mole of any gas occupies exactly 22.4L by volume at STP. Having this in mind, let us convert 22.4 to litres 1000cm³ = 1 L Then 294 cm³ = 294cm³/1000 = 0.294L Convert 0.294L to moles: If 22.4L = 1 mole Then 0.294L = 1 mole × 0.294/22.4 = 0.013125 moles Use the mole ratio in the equation to find the moles of the oxygen required: Mole ratio of SO₂:O₂ is 2:1 Therefore the moles of the oxygen used is 0.013125/2 moles = 0.0065625moles This is the number of moles of oxygen from the equation: We will use the same Avagadro's law to find the volume of oxygen from the moles If 1 mole occupies 22.4 L Then 0.0065625 moles will occupy ⇒ 0.0065625moles × 22.4/1 mole = 0.147 Litre The amount of oxygen used up in this reaction is 0.147 litres or 147cm³. The next step is to calculate the amount of air that contains 147cm³ of oxygen ⇒ If 21% = 147cm³ Then 100% = 147 × 100/21 = 700cm³ Therefore the volume of air required is 700 cm³ |
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| 30. |
Why reaction of higher order are less in no. |
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Answer» Answer: ACCORDING to the collision theory, the REACTIONS occurs due to the collision of the reactant molecules. Due to this very low probability of colliding of molecules, the HIGHER order reactions (>3) are QUITE rare. *Hope this will help you. plz give me a THANK and follow me. |
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| 31. |
What is the increase in entropy when 11.2 L of Ozare mixed with 11.2 L of H, at STP?(1) 0.576 J/K (2) 5.76 J/K |
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Answer» Answer: 2) 5.76 J/K Explanation: STP is the temperature of 273.15 K (0 °C, 32 °F) which is ABSOLUTE pressure based on 105 Pa (100 kPa, 1 bar).
S = 8.314 x 2.303 (V1 log N1 + v2 log N2)
= 8.314 x 2.303 (0.5 log 0.5+0.5 log 0.5)
= 8.314 x 2.303 (-0.3010)
=- 5.76 Therefore, the entropy is increased by -5.76. NOTE : "-" is negligible. |
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| 32. |
Based on which factor a solution is said to be diluted concenyrated or saturated |
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Answer» Answer: On the BASIS of of a SOLUTION, a solution is said to be dilute, concentrated or saturated. ACTUALLY, dilute is one which is having less amount of solute. Concentrated is one which which have high level of solute. *Hope this will help you. PLZ give me a thank and follow me. |
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| 33. |
What happen when zinc scrap is heated with concentrated NaOH solution ? |
Answer»
Explanation:
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| 34. |
(Refer common names in theFormula(i) NaOH(iv) KOH(v) CaCO314. Match the following: (Referbeginning of the book)Compound(a) Boric acid(b) Phosphoric acid(ii) SiO2(c) Nitrous acid(111) Na,C03(d) Nitric acid(e) Sulphurous acid(1) Sulphuric acid(vi) NaHCO3(g) Hydrochloric acid(vii) H S(h) Silica (sand)(viii) HO(i) Caustic soda(ix) PH,(sodium hydroxide)(1) Caustic potash(x) CH4(potassium hydroxide)(k) Washing soda(xi) NHZ(sodium carbonate)(1) Baking soda(xii) HCI(sodium bicarbonate)(m) Lime stone.(calcium carbonate)(xiii) H2SO3(n) Water(xiv) HNO(0) Hydrogen sulphide(p) Ammonia(xv) HNO,(q) Phosphine(xvi) HZBO,(r) Methane(xvii) H2PO4(xviii) H2SO4 |
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Answer» Identify each compound as an Arrhenius acid, an Arrhenius base, or NEITHER. KOH; H 2SO 4; C 2H 6. Answer. Arrhenius base; Arrhenius |
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| 35. |
Cloths dry faster in summer season than winter. give reason |
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Answer» humidity Explanation: |
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| 36. |
what is the meaning of rate of diappearance and rate of appearance pls explain tomorrow exam urgent pls ......... |
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Answer» rate of disappearance means that how fast a reactant is getting consumed. it is measured by change in reactant in an interval of time. so SIMILARLY rate of appearance means that how fast a product is getting FORMED. hence it is calculated by change in product in a given interval of time U may note that untill the reactant doesn't get consumed product doesn't get formed. so u can say that rate of appearance is EQUAL to rate of disappearance |
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| 37. |
Molecules of phosphorus and ammonia is |
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Answer» PHOSPHORUS P5 = 5 |
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| 38. |
13. Theobromine is?A) 1,3-dimethyxanthine B) 3,7-dimethyxanthineC) 1,3,7-trimethyxanthineD) None |
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| 39. |
Auto fire chemical formula? |
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Answer» Explanation: PERFORM Magic Tricks With FIRE Make a Sparkler Bubbles Crystals Chemical Reactions  Several chemical reactions result in combustion, WITHOUT requiring additional help from a match to get them going. Dorling Kindersley/Getty Images byAnne MARIE Helmenstine, Ph.D. Updated June 08, 2018 No matches or lighter are needed to start a fire. Here are four ways to make one using chemical reactions. Each of these techniques is simple and requires only three chemicals each. Chemical Fire #1 Potassium permanganate Glycerin Water Add a few drops of glycerin to a few crystals of potassium permanganate. Accelerate the reaction by adding a couple of drops of water. Chemical Fire #2 Acetone SULFURIC acid Potassium permanganate Soak a tissue with acetone to make it more flammable. Next, draw sulfuric acid into a glass pipette. Dip the pipette into potassium permanganate so that the tip of the pipette is coated with a few crystals. Dispense the sulfuric acid onto the tissue. The potassium permanganate and sulfuric acid will mix to produce manganese heptoxide and fire |
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| 40. |
What are the two versatile nature of carbon? |
Answer» Carbon is a versatile element and is found in many different chemical compounds, including those found in space. Carbon is versatile because it can form single, double, and triple bonds. It can also form chains, branched chains, and rings when connected to other carbon atoms.Carbon due to its PROPERTY of catenation POSSESSES a unique ABILITY to form bonds with other atoms of carbon, giving rise to large NUMBER of molecules and compounds having long chains of carbon, branched chains of carbon or carbon atoms arranged in rings and LINKED by single, double or triple bonds. |
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| 41. |
50. Which sample contains the smallest number ofatoms? (Atomic mass Li = 7, F = 19)(a) 1 g of CO2 (9)1061 g of C8H18 (1)(c) 1 g of C2H6 (g)(d) 1 g of LiF (s) |
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Answer» ... |
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| 42. |
Write the balanced equation of barium chloride + aluminium sulphate gives barium sulphate |
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Answer» The formula for barium chloride is BaCl2, aluminium sulphate is Al2(SO4)3, barium sulphate is BaSO4 and aluminium chloride is AlCl3, by the cross-valency rule. HENCE, the skeletal equation is: BaCl2 + Al2(SO4)3 --> BaSO4 + AlCl3 However, atoms of chlorine, aluminium and the polyatomic ion of sulphate are not BALANCED. The balanced equation would be: 3BaCl2 + Al2(SO4)3 --> 3BaSO4 + 2AlCl3 NOTE: The formulae can never be changed, i.e. the subscript must not change. Only the number of molecules can be changed, i.e. the change in number can be carried out only in front of the formula. A more informative WAY of expressing this reaction is by mentioning the PHYSICAL states. 3BaCl2(aq) + Al2(SO4)3(aq) --> 3BaSO4(ppt) + 2AlCl3(aq) |
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| 43. |
Why transition element has highest oxidation number in oxides and fluorides? |
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Answer» Ⓗⓔⓨ_______ |
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| 44. |
Why transition element has hight oxidisation number in oxides and florides? |
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Answer» Hey mate... i)The lowest OXIDE of transition metal is basic, the HIGHEST is amphoteric/acidic. (ii)A transition metal exhibits highest oxidation state in OXIDES and fluorides. ... This means that some of the valence electrons of the metal ATOM are not involved in bonding. As a RESULT, it can donate electrons and behave as a base. |
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| 45. |
Why it is easier to extract large dna fragments when we add acetate in te buffer? |
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Answer» Explanation: The BUFFER is needed to maintain the pH of the DNA solution at CLOSE to NEUTRAL level because if it can become ACIDIC through electrolysis. The electrical currents caused by the electrodes can cause water MOLECULES to dissociate and release H+ ions. |
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| 46. |
(D)TENW ColourWhich of the following is a mordantdye ?(A) Congo red(B) Aniline black(C) Indigo(D) Alizarin |
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Answer» ANILINE BLACK is your ANSWER . ❣️❣️❣️❣️❣️❣️❣️❣️❣️❣️❣️ |
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| 47. |
42. What is weight of Glucose (C6H1206)containing 1 gram atom of carbon ?(a) 18 gm(b) 180 gm(c) 30 gm(d) 1080 gm |
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Answer» The option c 180 is correct. Explanation: C6H12O6 The ATOMIC weight of 1 atom of CARBON = 13 The atomic weight of 1 atom of hydrogen = 1 The atomic weight of 1 atom of OXYGEN = 15 Then, C6H12O6 = 13*6+1*12+15*6 = 78+12+90 = 90+90 = 180 ANS PLEASE MAKE ME BRAIN LIST |
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| 48. |
At STP, the volume of 6.023 * 1023,the hydrogen atoms is |
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Answer» ......................... |
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| 49. |
Explain tha types of reactions with references to oxygen and hydrogen.illustrat pwith exampal |
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| 50. |
Why is the quantity of hydrogen double the amount of oxygen produced during electrolysis of water? |
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Answer» Ⓗⓔⓨ_______ |
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