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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
The concentration of hydrogen ion in a sample of soft drink is `3.8 xx 10^(-3)M`. What is its `pH`?A. `4.32`B. `5.12`C. `3.31`D. `2.42` |
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Answer» Correct Answer - D `pH = - log [3.8 xx 10^(-3)] = 2.42` Therefore, the pH of the solf drink is 2.42 and its is acidic. |
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| 52. |
A certain buffer solution contains equal concentartion of `X^(Theta)` and `HX`. The `K_(b)` for `X^(Theta)` is `10^(-10)`. The `pH` of the buffer isA. 4B. 7C. 10D. 14 |
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Answer» Correct Answer - A |
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| 53. |
pH of an acidic buffer is given byA. `pH = pK_(a) +log.(["salt"])/(["acid"])`B. `pH = pK_(a) -log.(["salt"])/(["acid"])`C. `pH = (1)/(2)pK_(a) +log.(["salt"])/(["acid"])`D. `pH = log K_(a) +log.(["salt"])/(["acid"])` |
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Answer» Correct Answer - A By Henderson equation `pH = pK_(a) + log .(["salt"])/(["acid"])` |
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| 54. |
For a reaction, `CH_(3)COOH(aq) hArr H^(+) (aq)+CH_(3)COO^(-)(aq)` or `HAc (aq) hArr H^(+)(aq)+Ac^(-)(aq)` Evaluate the pH of the solution resulting on addition of `0.05M` acetata ion to `0.05M` acid solution `(K_(a) = 1.8 xx 10^(-5))`A. `5.72`B. `3.87`C. `4.24`D. `4.74` |
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Answer» Correct Answer - D `{:(,HAc(aq)hArr,H^(+)(aq)+,Ac^(-)(aq)),("Initial conc"(M),0.05,0,0.05),("At equilibrium",0.05-x,x,0.05+x):}` concentration `(M)` `K_(a) = ([H^(+)][Ac^(-)])/([HAc]) ([(x)(0.05+x)])/((0.05-x))` As `K_(a)` is small for a very weak, `x lt lt 0.05` Hence, `(0.05+x) ~~ (0.05 -x)~~ 0.05` Thus, `1.8 xx 10^(-5) = ((x)(0.05+x))/((0.05-1)) = (x(0.05))/((0.05)) = x = [H^(+)]` `1.8 xx 10^(-5)M` `pH = - log (1.8 xx 10^(-5)) = 4.74` |
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| 55. |
The dissociation constant of a substituted benzoic acid at `25^(@)C` is `1.0xx10^(-4)`. The `pH` of `0.01M` solution of its sodium salt is |
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Answer» Correct Answer - 8 |
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| 56. |
When `100mL` of `1.0M HCl` was mixed with `100 mL` of `1.0 M NaOH` in an insulated beaker at constant pressure, a temperature increase of `5.7^(@)C` was measured for the beaker and its contents (Expt.1). Because the enthalpy of neutralisation of a strong acid with a strong base is constant `(-57.0kJmol^(-1))` this experiment couldbe used to measure the calorimeter constant. In a second experiment (Expt.2), `100mL` of `2.0M` acetic acid `K_(a)=2.0xx10^(-5))` was mixed with `100mL` of `1.0M NaOH` (under identical conditions to Expt. 1) where a temperature rise of `5.6^(@)C` was measured. Enthalpy of dissociation (in `kJ mol^(-1)`) of acetic acid obtained from the Expt. 2 isA. `1.0`B. `10.0`C. `24.5`D. `51.4` |
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Answer» Correct Answer - A |
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| 57. |
Indentify the correct order of solubility in aqueous mediumA. `CuS gt ZnS gt Na_(2)S`B. `ZnS gt Na_(2)S gt CuS`C. `Na_(2)S gt CuS gt ZnS`D. `Na_(2)S gt ZnS gt CuS` |
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Answer» Correct Answer - D |
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| 58. |
A solution which is `10^(-3)M` each in `Mn^(2+), Fe^(2+), Zn^(2+)`, and `Hg^(2+)` it treated with `10^(-16)M` sulphide ion. If the `K_(sp)` of `MnS, FeS, ZnS`and `HgS` are `10^(-15), 10^(-23), 10^(-20)`,and `10^(-54)`, respectively, which one will precipitate first?A. `FeS`B. `MgS`C. `HgS`D. `ZnS` |
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Answer» Correct Answer - C::D |
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| 59. |
How do we differentiate between `Fe^(3+)` and `Cr^(3+)` in group lll?A. By taking excess of `NH_(4)OH`B. By increasing `NH_(4)^(+)` ion concentrationC. By decreasing `OH^(-)` ion concentrationD. Both (a) and (c) |
| Answer» Correct Answer - D | |
| 60. |
In the titration of `NaOH` and HCI, which of the following indicators will be used ?A. Methyl organeB. Methyl redC. Both (a) and (b)D. None of (a) and (b) |
| Answer» Correct Answer - C | |
| 61. |
The `pK_(a)` of acteylsalicylic acid (aspirin) is `3.5`. The pH of gastric juice in human stomach is about `2-3` and the pH in the small intestine is about 8. Aspirin will be:A. ionised in the small intestine and stomachB. ionised in the stomach and almost unionised in the small intestineC. unionised in small intensity and stomachD. completely ionised in small intestine and stomach |
| Answer» Correct Answer - A | |
| 62. |
Solubility of `BaF_(2)` in a solution of `Ba(NO_(3))_(2)`, will be represented by the concentration term:A. `[Ba^(2+)]`B. `[F^(-1)]^(2)`C. `(1)/(2)[F^(-1)]`D. `2[NO_(3)^(-)]` |
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Answer» Correct Answer - C `Ba(NO_(3))_(2)` gives `Ba^(2+)` and `NO_(3)^(-)` ions, hence, concentration of `Ba^(2+)` ion increases. To keep `K_(sp)` constant, `[F^(-)]` decreases. Thus, it is represented as `(1)/(2)[F^(-)]` |
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| 63. |
The value of `pK_(w)` of waterA. increases with increase in temperatureB. decreases with rise in temperatureC. does not change with variation in temperatureD. increases till `50^(@)C` and there after decreases |
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Answer» Correct Answer - B On increasing temperature, `K_(w)` of water increases and hence `pK_(w)` decreases. |
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| 64. |
Amphoteric behaviour is shown byA. `H_(2)CO_(3)` and `AI_(2)O_(3)`B. `HCO_(3)^(-)` and `H_(2)O`C. `HCO_(3)^(-)` and `H_(3)O^(+)`D. `H_(2)CO_(3)` and `H_(2)O` |
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Answer» Correct Answer - B Amphoteric behaviour is that any species which acts as an acid as well as base. `underset("Acid")(HCO_(3)^(-)) rarr CO_(3)^(2-)+H^(+)` `underset("Base")(HCO_(3)^(-)) +H^(+) rarr H_(2)CO_(3)` `underset("Acid")(H_(2)O) rarr OH^(-) +H^(+)` `underset("Base")(H_(2)O)+H^(+) rarr H_(3)O^(+)` |
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| 65. |
For the reaction, `N_(2)(g)+3H_(2)(g) hArr 2NH_(3)(g)`, the units of `K_(p)` are …………A. `L mol^(-1)`B. `L^(2) mol^(-2)`C. `mol L^(-1)`D. No units |
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Answer» Correct Answer - B `N_(2)(g) +3H_(2)(g) hArr 2NH_(3)(g)` `K=([NH_(3)]^(2))/([N_(2)][H_(2)]^(3)) =([[mol)/(L)]^(2))/([[mol)/(L)][(mol)/(L)]^(3)) =[(mol)/(L)]^(-2) = L^(2)mol^(-2)` |
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| 66. |
`N_(2)+3H_(2)hArr2NH_(3)` Which is correct statement if `N_(2)` is added at equilibrium condition?A. The equilibrium will shift to forward direction because according to IInd law of thermodynamics, the entropy must increases in the direction of spontaneous reactionB. The condition for equilibrium is `G(N_(2))+3G(H_(2))=2G(NH_(3))` where `G` is Gibbs free energy per mole of the gaseous species measured at that partial pressure. The condition of equilibrium is unaffected by the use of catalyst, which increases the rate of both the forward and backward reactions to the same extentC. The catalyst will increase the rate of forward reaction by `alpha` and that of backward reaction by `beta`D. Catalyst will not alter the rate of either of the reaction |
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Answer» Correct Answer - B |
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| 67. |
For the pair of reactions given below, I. `N_(2)(g) +3H_(2)(g) hArr 2NH_(3)(g)` II. `(1)/(2)N_(2)(g) +(3)/(2)H_(2)(g) hArr NH_(3)(g)` If at a particular temperature, `K_(p1)` and `K_(p2)` are the equilibrium constants for reaction I and II respectively. thenA. `K_(p1) = 2K_(p2)`B. `K_(p1) = K_(p2)^(2)`C. `2K_(p1) = K_(p2)`D. `K_(p1) = K_(p2)` |
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Answer» Correct Answer - B `K_(p1) = (p_(NH_(3))^(2))/(p_(N_(2)).p_(H_(2))^(3))` .......(i) `K_(p2) = (p_(NH_(3)))/(p_(N_(1))^(1//2).p_(H_(2))^(3//2))` `K_(p2)^(2) = (p_(NH_(3))^(2))/(p_(N_(1))p_(H_(2))^(3))` ...(ii) On dividing Eq. (ii) by Eq.(i) `(K_(p1))/(K_(p2)) = 1` or `K_(p1) = K_(p2)^(2)` |
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| 68. |
Pure ammonia is placed in a vessel at a temperature where its dissociation constant `(alpha)` is appreciable. At equilibrium, `N_(2)+3H_(2)hArr2NH_(3)`A. `K_(p)` does not change significantly with pressureB. `alpha` does not change with pressureC. concentration of `NH_(3)` does not change with pressureD. concentration of hydrogen is less than that of nitrogen |
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Answer» Correct Answer - A |
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| 69. |
A ten-fold increase in pressure on the reaction, `N_(2)(g)+3H_(2)(g)hAr2NH_(3)(g)` at equilibrium, results in ……..in `K_(p)` |
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Answer» Correct Answer - no change |
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| 70. |
For a gaseous reaction `2BtoA`,the equilibrium constant `K_(p)` is ……to/than `K_(c)` |
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Answer» Correct Answer - smaller |
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| 71. |
For the reaction `H_(2)(g)+I_(2)(g)hArr2HI(g)` the equilibrium constant `K_(p)` changes withA. total pressureB. catalystC. the amount of `H_(2)` and `I_(2)` presentD. temperature |
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Answer» Correct Answer - D |
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| 72. |
When `NaNO_(3)` is heated in a closed vessel, oxygen is liberated and `NaNO_(2)` is left behind. At equilibriumA. addition of `NaNO_(2)` favours reverse reactionB. addition of `NaNO_(3)` favours forward reactionC. increasing temperature favours forward reactionD. increasing pressure favours reverse reaction |
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Answer» Correct Answer - C::D |
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| 73. |
One mole of `N_(2)O(g)` at `300K` is kept in a closed container under one atmosphere. It is heated to `600K` when `20%` by mass of `N_(2)O_(4)(g)` decomposes of `NO_(2)(g)`. The resultant pressureA. 1.2 atmB. 2.4 atmC. 2.0 atmD. 1.0 atm |
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Answer» Correct Answer - B |
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