Chemical & Ionic Equilibrium · JEE Main previous year questions

2005 9 questions

1. Q1612005 · 28 Apr 2005 · Shift 1

   If $\alpha$ is the degree of dissociation of $\mathrm{N}{\mathrm{a}}_2\mathrm{S}{\mathrm{O}}_4$, the vant Hoff's factor (i) used for calculating the molecular mass is :

   1. A.$1+\alpha$
   2. B.$1+2\alpha$
   3. C.$1-\alpha$
   4. D.$1-2\alpha$
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   Answer: B

2. Q1622005 · 28 Apr 2005 · Shift 1

   The solubility product of a salt having general formula $\mathrm{M}{\mathrm{X}}_2$, in water is: $4\times 10^{-12}$. The concentration of ${\mathrm{M}}^{2+}$ ions in the aqueous solution of the salt is :

   1. A.$2.0\times 10^{-6}\mathrm{M}$
   2. B.$4.0\times 10^{-10}\mathrm{M}$
   3. C.$1.0\times 10^{-4}\mathrm{M}$
   4. D.$1.6\times 10^{-4}\mathrm{M}$
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   Answer: C

3. Q1642005 · 28 Apr 2005 · Shift 1

   For the reaction $2\mathrm{N}{\mathrm{O}}_2(\mathrm{g})\rightleftharpoons 2NO(\mathrm{g})+{\mathrm{O}}_2(\mathrm{g})$, $({\mathrm{K}}_{\mathrm{c}}=1.8\times 10^{-6}\text{ at }184^{\circ }\mathrm{C})$ $(R=0.0831kJ/(mol.\mathrm{K}))$ When ${\mathrm{K}}_{\mathrm{p}}$ and ${\mathrm{K}}_{\mathrm{c}}$ are compared at $184^{\circ }\mathrm{C}$, it is found that :

   1. A.${\mathrm{K}}_{\mathrm{p}}$ is greater than ${\mathrm{K}}_{\mathrm{c}}$
   2. B.${\mathrm{K}}_{\mathrm{p}}$ is less than ${\mathrm{K}}_{\mathrm{c}}$
   3. C.${\mathrm{K}}_{\mathrm{p}}={\mathrm{K}}_{\mathrm{c}}$
   4. D.Whether ${\mathrm{K}}_{\mathrm{p}}$ is greater than, less than or equal to ${\mathrm{K}}_{\mathrm{c}}$ depends upon the total gas pressure
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   Answer: A

4. Q1652005 · 28 Apr 2005 · Shift 1

   Hydrogen ion concentration in $\mathrm{mol}/\mathrm{L}$ in a solution of $\mathrm{pH}=5.4$ will be :

   1. A.$3.98\times 10^{-6}$
   2. B.$3.68\times 10^{-6}$
   3. C.$3.88\times 10^6$
   4. D.$3.98\times 10^8$
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   Answer: A

5. Q1662005 · 28 Apr 2005 · Shift 1

   What is the conjugate base of $\mathrm{O}{\mathrm{H}}^{-}$?

   1. A.${\mathrm{O}}_2$
   2. B.${\mathrm{H}}_2\mathrm{O}$
   3. C.${\mathrm{O}}^{-}$
   4. D.${\mathrm{O}}^{-2}$
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   Answer: D

6. Q1672005 · 28 Apr 2005 · Shift 1

   An amount of solid $\mathrm{N}{\mathrm{H}}_4\mathrm{HS}$ is placed in a flask already containing ammonia gas at a certain temperature and $0.50\mathrm{atm}$ pressure. Ammonium hydrogen sulphide decomposes to yield $\mathrm{N}{\mathrm{H}}_3$ and ${\mathrm{H}}_2\mathrm{S}$ gases in the flask. When the decomposition reaction reaches equilibrium, the total pressure in the flask rises to $0.84\mathrm{atm}$. The equilibrium constant for $\mathrm{N}{\mathrm{H}}_4\mathrm{HS}$ decomposition at this temperature is :

   1. A.$0.30$
   2. B.$0.11$
   3. C.$0.17$
   4. D.$0.18$
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   Answer: B

7. Q1802005 · 28 Apr 2005 · Shift 1

   $$\begin{array}{llllll}\text{Electrolyte:}& \mathrm{KCl}& \mathrm{KN}{\mathrm{O}}_3& \mathrm{HCl}& \mathrm{NaOAc}& \mathrm{NaCl}\\ {\wedge }^{\infty }(\mathrm{Sc}{\mathrm{m}}^2\mathrm{mo}{\mathrm{l}}^{-1}):& 149.9& 145& 426.2& 91& 126.5\end{array}$$ Calculate ${\wedge }_{HOAc}^{\infty }$ using appropriate molar conductances of the electrolytes listed above at infinite dilution in ${\mathrm{H}}_2\mathrm{O}$ at $25^{\circ }\mathrm{C}$

   1. A.$517.2$
   2. B.$552.7$
   3. C.$390.7$
   4. D.$217.5$
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   Answer: C

8. Q1962005 · 28 Apr 2005 · Shift 1

   Among the following acids which has the lowest $\mathrm{p}{\mathrm{K}}_{\mathrm{a}}$ value?

   1. A.$\mathrm{C}{\mathrm{H}}_3\mathrm{COOH}$
   2. B.$\mathrm{HCOOH}$
   3. C.$(\mathrm{C}{\mathrm{H}}_3{)}_2\mathrm{COOH}$
   4. D.$\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{COOH}$
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   Answer: B

9. Q2052005 · 28 Apr 2005 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
   Show answer

   Answer: C