94420 + Interview Questions in Chemistry in Class 12

1.	Rate constant for a reaction H_(2) + I_(2) to 2HI is 49 , then rate constant for reaction 2 HI to H_(2) + I_(2) is
Answer» 7 `1//49` 49 21 Solution :For REVERSIBLE reaction RATE constant is also REVERSE .

Discussion

2.	Rateconstantdoesnotdepend uponunitof concentrationfor reactionwhoseorderis
Answer» ZERO first fractional infinite Answer :B

Discussion

3.	Rate constant.
Answer» Solution :The rate constant of a chemical REACTION is DEFINED as the rate of the chemical reaction when the CONCENTRATION (or active masses) of each reactant has unit VALUE.

Discussion

4.	Rate constant of a reaction depends upon:
Answer» temparature time initial concentration None of these. Answer :A

Discussion

5.	Rascing's process is employed for thecommerical preparation of:
Answer» Ehthyl CHLORIDE GRIGNARD's regent Chlorobenzane Ethanol Solution :NA

Discussion

6.	Rare earth metals belongs to the ....... column of moder periodic table
Answer» SOLUTION :3RD COLUMN

Discussion

7.	Rank the following subtances in order of increasing boiling points (lowestrarrhighest) : I. CH_(3)CH_(2)CH_(2)OH II. (CH_(3))_(2)CHOCH_(3) III. (CH_(3))_(3)COH"" IV. (CH_(3))_(4)C.
Answer» `IltIIIltIIltIV` `IIltIVltIIIltI` `IVltIIltIIIltI` `IIltIIIltIltIV` SOLUTION :it is the CORRECT ANSWER.

Discussion

8.	Rank the indicated C-C bonds in order of increasing bond length, and explain why you chose this order
Answer» SOLUTION :N/A

Discussion

9.	Rank the following dienes in order of increasin heat of hydrogenation.
Answer» SOLUTION :N/A

Discussion

10.	Rank the alkyl halides in orderof increasing reactivity in E_(2) reaction.
Answer» SOLUTION :`(a) P GT R gt Q (B) gt R gt P (C)Q gt P gt R`

Discussion

11.	Ranitidine is used as an ...
Answer» antioxidant antiseptic ANTACID ANTIBIOTIC SOLUTION : antacid

Discussion

12.	Range the following electrolytes in the increasing order of coagulating power for the coagulation of As_2S_3 sol (I) MgSO_4 (II) BaCl_2 (III) NaCl
Answer» `III GT I GTII` `IgtIIgtIII` `IIIgtIIgtI` `IgtIIIgtII` ANSWER :C

Discussion

13.	Ranitidine is a
Answer» ANTIHISTAMINE Antifertile Analgesic drug Tranquiliser ANSWER :A

Discussion

14.	Ranitidine belongs to which class of drugs.
Answer» SOLUTION :RANITIDINE BELONGS of ANTACIDS.

Discussion

15.	Radon was discovered by :
Answer» Dorn Ramsay Rayleigh None Answer :A

Discussion

16.	Random motion of colloidal particles is known as:
Answer» DIALYSIS Brownian MOVEMENT Electro-osmosis TYNDALL effect. Answer :B

Discussion

17.	Radon is a noble gas. It is radioactivity is used in the treatment of:
Answer» Typhold Cancer Cough and cold Thyroid Answer :B

Discussion

18.	Rancidity of oils and fats is due to:
Answer» PARTIAL hydrolysis by the ACTION of atmospheric moisture and oxidation of fatty acid to foul SMELLING products Aabsourbation of foul smelling ingredients from the air Fermentaion caused by MICRO - organisms Slow DECOMPOSITION of fatty acid Answer :A

Discussion

19.	Rancidity of oils is the effect of
Answer» EXPOSURE to LIGHT Exposure to OXYGEN of the ATMOSPHERE Exposure to MOISTURE and oxygen ofatmosphere Variation of atmosphere temperature Answer :A

Discussion

20.	Rancidity of butter is due to the formationof
Answer» BUTYRIC ACID Formaldehyde Acetic acid BENZOIC acid Answer :C

Discussion

21.	Ramsay - Rayleigh second method is based on
Answer» CONVERSION of `O_2 " to " CuO` Conversion of `N_2 " to " Mg_3N_2` Conversion of `O_2 and N_2` into oxides of nitrogen all Answer :C

Discussion

22.	Ramsay was awarded Noble prize for the discovery of rare gases in:
Answer» 1900 1902 1904 1910 Answer :C

Discussion

23.	Ralate the electronic configuration of elements and their properties in the classification of elements.
Answer» Solution :All the elements are divided into four types on the BASIS of their properties and electronic configurations. They are : (i) Noble gas elements (ii) Representative elements (iii) Transition elements and (iv) Inner transition elements. (i)Noble gas elements : Elements in which the outermosts and p sub-shells are completely filled are called inert gas elements. "0" group elements belong to this type. Due to completely filled shells they show chemical inertness and possess more stability. The general outer configuration of these elements is `ns^(2) np^(6)` (except helium). The configuration of helium is `1s^(2)`. They are called noble GASES. (ii) Representative elements : Elements in which the outermost s and p sub shells ae incompletely filled are called representative elements. These elements are so named because they represent most of the chemical reactions known. Elements of s-block and p-block (except '0' group) belong to this type. The general outer electronic configuration of these elements is `ns^(1), ns^(2), ns^(2)np^(1)` to `ns^(2)np^(5)`. These elements enter into chemical reactions either by losing or gaining or sharing of electrons. Many of the non-metals, metalloids and some metals belong to this type. (iii) Transition elements : Elements in which the outermost and penultimate shells are partially filled are called transition elements. They beolong to d-block. Their general configuration is `(n-1)d^(1-9) ns^(1-2)`. They are so named because there is a gradation from electro +ve nature to electro -ve nature. They possess the following CHARACTERISTIC properties. (1) They exhibt variable OXIDATION states. (2) They form coloured compounds. (3) They are all paramagnetic. (4) They and their oxides acts as catalysts. (5) They form alloys and interstitial compounds. (6) They form complex compounds. (iv) Inner tarnsition elements: Elements in which the outermost, penultimate and antipenultimate shells are partially filled are called Inner transition elements. They belong to f-block and are placed separately at the bottom of the table. Their general outer configuration is `(n-2)f^(1-14) (n-1)d^(0,1)ns^(1-2)`. They are so named as they represent a transition of physical and chemical properties among them. There are two series of inner transition elements corresponding to 4f and 5f series. 4f series are called lanthanides and elements of 5f series are called ACTINIDES. Lanthanides are also called rare earths. Majority of actinides are synthetic.

Discussion

24.	Raju and his father were going in a boat in the river. Raju's father was going to throw away the cell used in watches and hearing aids into the water. Raju prevented him doing so. (a) As a student of chemistry , why would you advise Raju's father not to throw the cell in the water body? (b) What is the value associated with the above decision ?
Answer» Solution :(a) The watch cells are made up of MERCURY . This mercury will pollute the WATER. Water CONTAMINATED with mercury leads to accumulation of mercury in the body of fishes and other aquatic life. (b) It helps in keeping the ENVIRONMENT safe from pollution DUE to mercury.

Discussion

25.	Raising thetemperatue of an equlibrium system
Answer» Favours the oxothermic REACTION only Favours the endotermic reaction only Favours both the exothermic and cindothermic reactions Favours NEITHER the exothermic nor endotermic reactions SOLUTION :According to Le chatelier's prnciple.

Discussion

26.	Rain water sometimes contains NH_4NO_3 because lighting in the sky causes the air to react with produce oxides of nitrogen and
Answer» `H_2` `NH_3` `CO_2` NOBLE gas Answer :B

Discussion

27.	Rain containg dissolved air pollutants like oxides of S, N are referred to as :
Answer» ARTIFICIAL RAIN ACID rain Hails None of these Answer :B

Discussion

28.	Rahul visited the house of the friend Shayam and found that all the water laps were rusted. On equiry, he came to know that these were iron taps. Rahul advised his friend to use either chrome plated or nickel plated taps. Shyam accepted his advice. On the basis of above passage give the answer of the following questions: (i) Why did iron tap get rusted? (ii) What was the purpose of chrom plating or nickel plating? (iii) What is the value associated with this?
Answer» Solution :(i) Iron is prone to rust. It GET rusted when kept in opne. (ii) The purpose of depositng a layer of CHROMIUM or nickel or the surface of iron is to check RUSTING. (iii) General AWARENESS (b) Friendship (c ) Knowledge of chemistry put to USE.

Discussion

29.	Railway wagon axles are made by heating iron rods embedded in charcoal powder. This process is known as
Answer» tempering CASE HARDENING sherardising annealing Solution :Case hardening.

Discussion

30.	Raghav's grandfather is not only obese but is also diabetic. Therefore, he suggested his grandfather not to take sugar but instead he should take artificial sweeteners. After reading the above passage, answer the following questions : (i) What values are expressed by Raghav? (ii) Name the artificial sweetener recommended for diabetic patients. What are its uses? (iii) Name an artificial sweetener which is a derivative of a dipeptide. Also write the names of the two alpha-amino acids from which this dipeptide is derived. What are its advantages and disadvantages?
Answer» Solution :(i) Raghay expressed concern about the health and well being of his grandfather because sugar affects the functioning of the vital organs, i.e.,heart, liver and kidney of the BODY. (ii)Saccharin is the artificial sweetener recommended for diabetic patients. It is not metabolized and do not have any calorific value of food. It is secreted as such in urine. (III)Aspartame is the methyl ester of the dipeptide derived from the two AMINO acids: phenylalanine andaspartic acid. Advantages. It is roughly 100 times as sweet as sucrose. Therefore, only a small amount is required Disadvantages. People suffering from the DISEASE PHENYLKETONURIA cannot use aspartame since the metabolism causes the conversion of aspartame to phenylpyruvic acid. Accumulation of phenylpyruvic acid is harmful especially in infants due to brain damage and mental retardation

Discussion

31.	Raffinose on hydrolysis gives
Answer» GLUCOSE, FRUCTOSE, GALACTOSE Fructose, Glucose, MALTOSE Galactose, Fructose, MANNOSE Maltose, Fructose, Galactose Answer :A

Discussion

32.	Raffinose is an example of
Answer» trisaccharide disaccharide monosaccharide polysaccharide Answer :A

Discussion

33.	Raffinose on hydrolysis forms :
Answer» Glucose Fructose Galactose All Answer :D

Discussion

34.	Raffinose is
Answer» trisaccharide disaccharide monosaccharide polysaccharide Solution :Monosaccharides do not hydrolyse, disaccharides give two molecules of monosaccharides, trisaccharides give THREE molecules of monosaccharides and polysaccharides give many molecules of monosaccharides on HYDROLYSIS. `UNDERSET"Raffinose"(C_18H_32O_16)+H_2O to ` glucose + fructose + galactose `THEREFORE ` Raffinose is a trisaccharide

Discussion

35.	Raffinose is :
Answer» MONOSACCHARIDE DISACCHARIDE Trisaccharide None ANSWER :C

Discussion

36.	Rae law for the reaction A+2BtoC is found to be Rate =K[A][B] concentration of reactant .B. is doubled ,keeping the concentration of .A. constant ,the value of rate constant will be……
Answer» the same doubled quadrupled halved Solution :Initial RATE `r_(1)`=K[A][B] If the concentration of B is double than new concentration [2B] So `r_(2)`=k[A][B]=2K [A][B] `therefore (r_(2))/(r_(1))=2` so the rate is double

Discussion

37.	Radon undergoesdecay by alpha- emission ""_(86)^(222) Rn overset(t_(1//2) = 3.8 "days") (to) ""_(84)^(218) Po + ""_(2)^(4) He Which of the following statements will be true for this decay process ?
Answer» If the initial AMOUNT of RADON was 1 mg , the amount of radon left after 11.4 days will 0.125 mg Activity of radon after 7.6 days will be `N_(0) xx (5.3 xx 10^(-7)) s^-1` where `N_0` is the original number of atoms of the radon The decay constant of radon is `2.1 xx 10^(-6) S^(-1)` 60% of the radon will decay in 5 days APPROXIMATELY Solution :1 mg `overset(3.8 "days")(to) (1)/(2) overset(3.8 "days") (to) (1)/(4) overset(3.8 "days") (to) (1)/(8) , N_(0) 0.5 ((N_(0))/(2)) 0.25 ((N_(0))/(4)) 0.125` (b) `A_(0) = ((0.693)/(3.8)) xx N_(0) , N_(0) = (( 1 xx 10^(-3))/(222) xx 6 xx 10^(23)) . A_(t) = ((0.693)/(3.8)) xx N_(t) darr` 76 days `A_(t) = ((0.693)/(3.8)) xx ((N_(0))/(4)) , N_(t) = ((N_0)/(4)) = ((1 xx 10^(-3))/(222) xx 6 xx 10^(-23) xx (1)/(4))` `A_(t) = ((0.693)/(3.8 xx 24 xx 60 xx 60) xx (N_0)/(4)) = (5.277 xx 10^(-7) xx N_(0)) sec^(-1)` (c) `lambda = ((0.693)/(t_(1//2))) = ((0.693)/(3.8 xx 24 xx 60 xx 60)) = (((0.693)/(3.046)) xx 10^(-6) ) sec^(-1) = 2.1 xx 10^(-6) sec^(-1)` (d) `((0.693)/(3.8)) xx t = 2.303 xx log ((600)/(400)) , t = ((0.4 xx 3.8)/(0.3040)) = 5`

Discussion

38.	Radon has low ionisation potential and empty d-orbitals in the valence shell. Still it does not form compounds with other elements. Why?
Answer» Solution :Radon is radioactive element with EXTREMELY low half-life period. During this period it is difficult to form COMPOUNDS. Hence, it does not COMBINE with other ELEMENTS.

Discussion

39.	radius of the bohr's orbit for hydrogen like spacies is given by which expression?
Answer» `0.529n^2barA` `0.529n^2/ZbarA` `0.529Z/n^2barA` `0.5291/n^2barA` ANSWER :B

Discussion

40.	Radium has atomic weight 226 and a half-life of 1600 years. The number of disintegrations produced per second from 1g are
Answer» `4.8 XX 10^(10)` `9.2 xx 10^(6)` `3.7 xx 10^(10)` Zero Solution :`R = (0.693)/(t_(1//2)) xx N_(0) = (0.693)/(1600 xx 365 xx 24 xx 60 xx60) xx(6.023 xx 10^(23))/(226)` `= 3.7 xx 10^(10)`dps

Discussion

41.	Radium is obtained from
Answer» Haematite Pitchblende Monazite None of these Answer :B

Discussion

42.	Radium is obtained from:
Answer» Pitchblende Haematite Monazite None of these Answer :A

Discussion

43.	Radioisotopes have been used in treatment of certain diseases. For treatment of cancerous tumours, the radioisotope used was:
Answer» Co-60 U-235 Pu-239 Th-231 Answer :A

Discussion

44.	Radium disintegrates to give radon. Write chemical equation as well as rate equation.
Answer» Solution :`.^(226)RA to .^(4)He+.^(222)RN` Radioactive decay takes place by first ORDER KINETICS. Rate =K[Ra]

Discussion

45.	Radioactivity was discovered by
Answer» Henry Becqueral Rutherford J.J. Thomson MADAM Curie Solution :Henry BECQUEREL noticed the emission of PENETRATING rays from potassium uranyl sulphate and Madam Curie NAMED it as RADIOACTIVITY

Discussion

46.	Radioactivity of a radioactive element remains (1)/(10) of the original radioactivity after 2.303 seconds. The half-life period is
Answer» 2.303 0.2303 0.693 0.0693 Solution :`2.303 = (2.303)/(0.693) XX t_(1//2) LOG 10`

Discussion

47.	Radioactivity of a sample (Z = 22) decreases 90% after 10 years. What will be the half-life of the sample ?
Answer» 5 years 2 years 3 years 10 years SOLUTION :`k = (2.303)/(t) log (a)/(a - x) = (2.303)/(10) log 100/10` `k = (2.303)/(10)` `t_(1//2) = (0.693)/(2.303) XX 10 = 3` YRS.

Discussion

48.	Radioactivity of neptunium stops when it is converted to
Answer» Bi Rn Th Pb Solution :Bi is a STABLE END PRODUCT of Neptunium SERIES

Discussion

49.	Radioactivity of a sample (Z =22) decrease 90% after 10 years . What will be the half -life of the sample
Answer» 5 YEARS 2 years 3 years 10 years SOLUTION :`k= (2.303)/(t) "LOG" (a)/(a-x) = (2.303)/(10) "log" (100)/(10)` `k = (2.303)/(10)` `t_(1//2) = (0.693)/(2.303) xx 10 = 3 ` yrs.

Discussion

50.	Radioactive substance has a constant activity of 2000 disintegrations per minute. The material is separated into two fractions, one of which has an initial activity of 1000 disintegration per second while the other fraction decays with t_(1//2) = 24 hours. The total activity in both sample after 48 hours of separation is :
Answer» 1500 1000 1250 2000 Answer :d

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Rate constant for a reaction H_(2) + I_(2) to 2HI is 49 , then rate constant for reaction 2 HI to H_(2) + I_(2) is

Rateconstantdoesnotdepend uponunitof concentrationfor reactionwhoseorderis

Rate constant.

Rate constant of a reaction depends upon:

Rascing's process is employed for thecommerical preparation of:

Rare earth metals belongs to the ....... column of moder periodic table

Rank the following subtances in order of increasing boiling points (lowestrarrhighest) : I. CH_(3)CH_(2)CH_(2)OH II. (CH_(3))_(2)CHOCH_(3) III. (CH_(3))_(3)COH"" IV. (CH_(3))_(4)C.

Rank the indicated C-C bonds in order of increasing bond length, and explain why you chose this order

Rank the following dienes in order of increasin heat of hydrogenation.

Rank the alkyl halides in orderof increasing reactivity in E_(2) reaction.

Ranitidine is used as an ...

Range the following electrolytes in the increasing order of coagulating power for the coagulation of As_2S_3 sol (I) MgSO_4 (II) BaCl_2 (III) NaCl

Ranitidine is a

Ranitidine belongs to which class of drugs.

Radon was discovered by :

Random motion of colloidal particles is known as:

Radon is a noble gas. It is radioactivity is used in the treatment of:

Rancidity of oils and fats is due to:

Rancidity of oils is the effect of

Rancidity of butter is due to the formationof

Ramsay - Rayleigh second method is based on

Ramsay was awarded Noble prize for the discovery of rare gases in:

Ralate the electronic configuration of elements and their properties in the classification of elements.

Raising thetemperatue of an equlibrium system

Rain water sometimes contains NH_4NO_3 because lighting in the sky causes the air to react with produce oxides of nitrogen and

Rain containg dissolved air pollutants like oxides of S, N are referred to as :

Railway wagon axles are made by heating iron rods embedded in charcoal powder. This process is known as

Raffinose on hydrolysis gives

Raffinose is an example of

Raffinose on hydrolysis forms :

Raffinose is

Raffinose is :

Rae law for the reaction A+2BtoC is found to be Rate =K[A][B] concentration of reactant .B. is doubled ,keeping the concentration of .A. constant ,the value of rate constant will be……

Radon undergoesdecay by alpha- emission ""_(86)^(222) Rn overset(t_(1//2) = 3.8 "days") (to) ""_(84)^(218) Po + ""_(2)^(4) He Which of the following statements will be true for this decay process ?

Radon has low ionisation potential and empty d-orbitals in the valence shell. Still it does not form compounds with other elements. Why?

radius of the bohr's orbit for hydrogen like spacies is given by which expression?

Radium has atomic weight 226 and a half-life of 1600 years. The number of disintegrations produced per second from 1g are

Radium is obtained from

Radium is obtained from:

Radioisotopes have been used in treatment of certain diseases. For treatment of cancerous tumours, the radioisotope used was:

Radium disintegrates to give radon. Write chemical equation as well as rate equation.

Radioactivity was discovered by

Radioactivity of a radioactive element remains (1)/(10) of the original radioactivity after 2.303 seconds. The half-life period is

Radioactivity of a sample (Z = 22) decreases 90% after 10 years. What will be the half-life of the sample ?

Radioactivity of neptunium stops when it is converted to

Radioactivity of a sample (Z =22) decrease 90% after 10 years . What will be the half -life of the sample