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. |
For a diatomic molecule AB, the electronegativity difference between A and B=0.2028 sqrt triangle where triangle=[Bond energy of AB- Geometric mean of the bond energies of A_2 and B_2]. The electonegativities of fluorine and chlorine are 4.0 and 3.0 respectively and the bond energies are of F-F : 38 kcal mol^-1 and Cl-Cl : 58 kcal mol^-1. The bond energy of Cl-F is: |
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Answer» 71 kcal/mol |
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| 2. |
For a decomposition reaction the value of rate constant k at two different temperature are given below : k_1 = 2.15xx10^(-8)" L mol"^(-1)s^(-1)" at "650K""k_2=2.39xx10^(-7)"l mol"^(-1)s^(-1)"at "700K Calculate the value of activation energy for this reaction . (R=8.314"JK "^(-1)mol^(-1)) |
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Answer» SOLUTION :Here `k_1=2.15xx10^(-8)"L mol"^(-1)s^(-1)""k_2=2.39xx10^(-7)"L mol"^(-1)s^(-1)` `T_1=650K, T_2=700 K and ""R=8.314"JK "^(-1)"mol"^(-1)` Using the formula `log k_2/k_1 = (E_a)/(2.303R)[(T_2-T_1)/(T_1T_2)]` `log (2.39xx10^(-7))/(2.15xx10^(-8))=E_a/(2.303xx8.314)[(700-650)/(650xx700)]` log `1.111xx10 = E_a/(19.147)xx50/(455000)` `1.0457=E_a/(19.147)XX1/(9100)` `E_a = 182202.812J " or " 182.203kJ` |
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| 3. |
For a d-electron, the orbital angular momentum is |
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Answer» `sqrt6 ħ` |
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| 5. |
For a d-electron the orbital angular momentum is |
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Answer» h ORBITAL ANGULAR MOMENTUM = `sqrt(l(l+1))h/(2pi)` `=sqrt(2(2+1))h/(2pi)=sqrt6h/(2pi)=sqrt6h` |
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| 6. |
For a cyclic process, which of the following is not true? |
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Answer» `DeltaH=0` `DeltaE=0, DeltaH=0` and `DeltaG=0`. As all depend UPON final state and INITIAL state, W doesn.t depend on path FOLLOWED. |
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| 7. |
For a cyclic process |
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Answer» W = 0 |
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| 8. |
For a crystal, the angle of diffraction (20) is 90^@ and the second order line has a d value of 2.28 A^@. The wavelength (in A^@) of X-rays used for Bragg's diffraction is |
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Answer» `1.61Å` |
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| 9. |
For a cubic lattice edge length of unit cell is 5A^(0) and density is 2gcc^(-1). Calculate the radius of an atom, if gram atomic weight is 75 g mol^(-1). |
| Answer» SOLUTION :`2.17 A^(@)` | |
| 10. |
For a crystal system a=b=c and alpha=beta=gammane90^(@) |
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Answer» Tetragonal Tetragonal `a=bnec alpha=beta=gamma=90^(@)` Hexagonal `a=bnec alphanebeta=90^(@),gamma=120^(@)` Rhombohedral `a=b=c alpha=beta=gammane90^(@)` Monoclinic `anebnec alpha=gamma=90,betane90^(@)` |
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| 11. |
For a crystal of sodium chloride, state : The structural arrangement of the sodium chloride crystal. |
| Answer» SOLUTION :`Cl^(-)` ION have fcc arrangement and `NA^+`IONS occupy all the ocetahedral sites. Each `Na^+` ion is surrounded by 6 `Cl^(-)` ions and each `Cl^(-)` ion is surrounded by 6 `Na^+` ions. | |
| 12. |
For a crystal of sodium chloride, state : The number of sodium ions and chloride ions present in unit cell of sodium chloride. |
| Answer» SOLUTION :`4 NA^+ , 4 CL^(-)` | |
| 13. |
How many sodium ions and chloride ions are present in a unit cell of sodium chloride ? |
| Answer» SOLUTION :`4 NA^+ , 4 CL^(-)` | |
| 14. |
For a crystal of diamond, state : The type of lattice in which it crystallizes. |
| Answer» Solution :GIANT network TYPE with fcc ARRANGEMENT of C atoms | |
| 15. |
For a crystal of diamond, state : The number of carbon atoms present per unit cell. |
| Answer» Solution :Number of particles PER UNIT CELL is 4. | |
| 16. |
For a crystal of diamond, state : The hybridization of the carbon atom. |
| Answer» SOLUTION :`sp^3` HYBRIDIZATION | |
| 17. |
For a covalent solid, the units which occupy lattice points are |
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Answer» Atoms |
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| 18. |
For a compound to be purified by steam distillation : |
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Answer» IMPURITIES must be non-volatile |
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| 19. |
For a compound solution of a weak electrolyte A_(x)B_(y) of concentration 'C', the degree of dissociation alpha is given as |
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Answer» `alpha = sqrt(K_(eq)//C(x+y))` Where `alpha` = DEGREE of dissociation. `:. K_(eq) = (((Cx alpha)^(x)(Cy alpha)^(y))/(C(1-alpha)))` For concentrated solution of WEAK electrolyte, `alpha` is very small. Therefore, `(1-alpha) ~~ 1`. `:. alpha = ((K_(eq))/(C^(x+y-1).X^(x).y^(y)))^((1)/(x+y))`. |
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| 20. |
For a complex reaction…… |
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Answer» order of overall reaction is same as molecularity of the slowest STEP. (D)The product is form when reactant is there.So molecularity of reaction can.t be zero or fractional |
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| 21. |
For a complex reaction |
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Answer» ORDER of overall reaction is same as MOLECULARITY of the SLOWEST step |
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| 22. |
For a complex reaction ………………. . |
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Answer» ORDER of overall REACTION is same as molecularity of the slowest step |
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| 23. |
For a complex reaction : |
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Answer» ORDER of overall reactionis same as molcularity of the slowest step (PROVIDED slowest step is having no reaction intermediate) |
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| 24. |
For a complex reaction _________ |
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Answer» Order of OVERALL REACTION is same as molecularity of the slowest STEP. |
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| 25. |
For a chemical reaction Y_2 + 2Z toProduct,rate conctrolling step is Y + 1/2 Z to Q If the concentration of Z is doubled, the rate of reaction will |
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Answer» remain the same `:.("Rate"_2)/("Rate"_1)=(k[A][2Z]^(1//2))/(k[Y][Z]^(1//2))=(2)^(1//2)=sqrt2` |
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| 26. |
For a chemical reaction……can never be a fraction |
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Answer» Order |
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| 27. |
For a chemical reaction Y_(2)+2Zto Product rate controlling step is Y+1//2ZtoQ. If the concenntration of Z is doubled the rate of reactin will |
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Answer» REMAIN the same |
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| 28. |
For a chemical reaction variation in rate with conc. Is shown below : (i) What is the order of the reaction ? (ii) What are the units of rate constant k for the reaction ? |
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Answer» Solution :(i) ACCORDING to graph there is no CHANGE in concentration with rate so this is zero order reaction. (II) Unit of (zero order reaction) rate CONSTANT is mol `L^(-1) s^(-1)`. |
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| 29. |
For a chemical reaction, variation in concentration , in [R] vs time (min) plot is shown: i) What is the order of the reaction? ii) What are units of rate constant, k for reaction? |
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Answer» SOLUTION :i) The REACTION is of first order. ii) Units of rate constant(k) `=min^(-1)` III) `t_(1//2)` remains constant since it is independent of `[R]_(0)` i.e., initial CONCENTRATION of reactants. iv) For the plot (or graph). |
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| 30. |
For a chemical reaction, variation in concentration [A] vs time (s) plot in given below: i) Predict the order of the reaction. ii) What does the slope of the line and intercept indicate ? iii) What is the unit of rate constant(k)? |
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Answer» SOLUTION :i) The reaction is of zero ORDER. ii) The SLOPE of the line indicates rate constant (k) and INTERCEPT represents `[R]_(0)` iii) Units of k = `molL^(-1)s^(-1)`
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| 31. |
For a chemical reaction to take place, what should be the value of DeltaG ? |
| Answer» SOLUTION :NEGATIVE | |
| 32. |
For a chemical reaction, Delta C_(p) is negative (Delta C_(p) lt 0). The heat required to increase temperature of reactans of this reaction by a certain amount =q_(1) and heat required to increase temperature of products of the same reaction by same amount =q_(2), Relate q_(1) and q_(2) |
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Answer» |
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| 33. |
For a chemical reaction, DeltaG will always be negative if |
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Answer» `DeltaH` and `TDELTAS` both are positive `DeltaG=DeltaH-TDeltaS` From Gibbs-Helmholtzequation, it is clear that `DeltaG` will ALWAYS be negative, if `DeltaH` is negative and `TDeltaS` is positive. |
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| 34. |
For a chemical reaction, mA to xB, the rate law is r=k[A]^2. If the concentration of A is doubled, the reaction rate will be |
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Answer» doubled When CONCENTRATION of A is doubled , `r=K[2A]^(2)` `r=4k[A]^(2)` |
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| 35. |
For a chemical reaction Ato products, the following equation is found to be followed, logK=16.398-2800/T At 27^(@)C the rate contant of the reaction is ______ |
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Answer» `1.16xx10^(5)` |
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| 36. |
For a chemical reaction Ato Products, the rate of disappearance of A is given by: (dC_(A))/(dt)=(K_(1)C_(A))/(1+K_(2)C_(A)) at low C_(A), the reaction is of the _________order with rate constant_________(Assume K_(1), K_(2) are lesser than 1) |
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Answer» `I,K_(1)//K_(2)` |
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| 37. |
For a chemical reaction Ato products, the following equation is found to be followed, logK=16.398-2800/T Activation energy of the reaction is _____________K.Cal |
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Answer» 128.13 |
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| 38. |
For a chemical reaction Ato products, the following equation is found to be followed, logK=16.398-2800/T Arrhenius factor for the reaction is ______ |
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Answer» `2.5xx10^(16)` |
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| 39. |
For a chemical reaction at 27^(@)C, the activation energy is 600 R. The ratio of the rate constants at 327^(@)C to that of at 27^(@)C will be |
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Answer» 2 or, In`(k_2)/(k_1)=(600R)/(R) ((1)/(300)-(1)/(600))` or, In `(k_2)/(k_1)=(600R)/(R)((2-1)/(600))=1` or, In`(k_2)/(k_1)`=In e(`therefore` In e=1) `(k_2)/(k_1)=e` |
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| 40. |
For a chemical reaction at constant P, Delta H is equal to |
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Answer» zero |
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| 41. |
For a chemical reaction at constant P and V. Delta H is equal to |
| Answer» Answer :A | |
| 42. |
For a chemical reaction at 27^(@)C , the activation energy is 600 R . The ratio of the rate constants at 327^(@)C to that of at 27^(@)C will be |
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Answer» 2 or , ln `(K_(2))/(K_(1)) = (600R)/(R) ((2-1)/(600)) = 1 ` ln `(K_(2))/(K_(1))` = ln e `"" (K_(2))/(K_(1)) = e` |
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| 43. |
For a chemical reaction ArarrB, it is found that the rate of reaction doubles when the conc, of 'A' is increased four times. The order of reaction is |
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Answer» 0 |
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| 44. |
For a chemical reaction aAtoB,log[-(d[A])/(dt)]=log[(d[B])/(dt)]+0.3 then find the approximate ratio and of a and b |
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Answer» `LOG((dA)/(dt))=log((DB)/(dt))+log(a/b)` So `log (a/b)=0.3=log2,a/b=2` |
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| 45. |
For a chemical reaction A_2 +2 B toProducts, the rate con trolling step is A=1/2B to C.If the cone. of B is tripled, the rate of reaction will |
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Answer» remain the same `A + 1/2B to C, " rate LOW is,"(dx)/(dt)=k[A][B]^(1//2)` On TRIPLING the concentration of B, the rate will become `(3)^(1//2)= 1.732` times of the original rate. |
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| 46. |
For a chemical reaction A to B , the rate of the reaction is 2 xx 10^(-3) mol dm^(-3) s^(-1) . When the initial concentration is 0.05 mol dm^(-3) . The rate of the same reaction is 1.6 xx 10^(-2) mol dm^(-3) s^(-1) when the initial concentration is 0.1 mol dm^(-3) . The order of the reaction is |
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Answer» 0 rate = `k [A]^(n)` where , k = rate constant , n = order of reaction [A] = concentration of reactant given , `"rate"_(1) = 2 xx 10^(-3) "mol" dm^(-3) s^(-1)` `[A_(0)] = 0.05 ` mol `dm^(-3)` `"rate"_(2) = 1 . 6 xx 10^(-2)` mol `dm^(-3) s^(-1)` `(A_(0)) = 0.1` mol `dm^(-3)` `therefore 2 xx 10^(-3) = k [0.05]^(n) "".... (i)` `1.6 xx 10^(-2) = k[0.1]^(n) "".... (ii)` DIVIDE (i) by (ii) `implies (2 xx 10^-3)/(1.6 xx 10^(-2)) = ([0.05]^(n))/([0.1]^(n)) = ([0.05]^(n))/(2^(n)[0.05]^(n))` `implies (1)/(2^(n)) = (1)/(8) implies n = 3, "" therefore` Order of reaction = 3 . |
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| 47. |
For a chemical reaction, A to products, the rate of reaction doubles when the concentration of 'A' is increased by a factor of 4, the order of reaction is- |
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Answer» 2 |
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| 48. |
For a chemical reaction A to B, it was found that concentration of B increases by 0.20 mol L^(-1) in half an hour. What is the average rate of the reaction? |
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Answer» `Delta[B]=0.20 mol L^(-1), Deltat=0.5 hour.` `THEREFORE` AVERAGE rate =`(Delta[B])/(Deltat) = (0.20 mol L^(-1))/(0.5 hr)=0.40 mol L^(-1)hr^(-1)` |
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| 49. |
For a chemical reactionA to B it is found that the rate of reaction doubles , when the concentration of A is increased four times . The order in A for this reaction is |
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Answer» SOLUTION :`r = k[A]^(m)` also 2r = `k[4A]^(m) , (1)/(2) = ((1)/(4))^(m)` `therefore m = (1)/(2).` |
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| 50. |
For a chemical reactio , variation in the concentration [R] Vs time (s) plot is given: For this chemical reaction, write/draw: i) What is the order of the reaction? ii) What are the units of the rate constant (k)? iii) Give the relationship between k and t_(1//2) (half life period) iv) What does the slope of the aboveline indicate? v) Draw the plot log [R]_(0)/[R] Vs time (s). |
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Answer» Solution :i) The reaction is of FIRST ORDER. II) Units of RATE constant (k) = `("time")^(-1)` or `s^(-1)` iii)Rate constant (k) = `(0.693)/(t_(1//2)` (iv) The slope of the line is equal to`-(k)` v) for the graph |
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