# Chemical equilibrium class 11 questions

Question 1
(a)Write the $K_{SP}$ expression of the zirconium phosphate $({\rm Zr}^{4+})_3({\rm PO}_4^{3-})_4$.
(b) Calculate the pH of ${10}^{-8}$ M HCl.
(c)which of the following salt will give highest pH in water
(i) NaCl
(ii) KCl
(iii)$CuSO_4$
(iv) $Na_2CO_3$
(d) Write the solubility product expression for the following salts: Silver chromate, barium chromate, ferric hydroxide, lead chloride and mercurous iodide.
(e) which of the following is the buffer solution?
(i)HCl and KCl
(ii) $NaNO_2$, $HNO_2$
(iii) NaOH and HCl
(iv) $NH_4NO_3$, $HNO_3$
(f)What is the pH Scale?
(g)What is lewis Acid and base?
(h)The solubility of a lead iodide ${\rm Pbl}_2$ is S mol/L. Calculate its $K_{sp}$.
(i)The solubility of magnesium hydroxide is 0.0093 mol/L, calculate its $K_{sp}$.
(j)The solubility of ${\rm CaF}_2$ in water at 298 K is $1.7 \times 10^{-3}$ grams per $100cm^3$. Calculate the solubility product of ${\rm CaF}_2$ at 298 K.
(k)The Ksp of lead fluoride is $2.7 \times 10^{-8}$. Calculate the molar solubility and solubility in g/L of ${\rm PbF}_2$.
(l)Determine the solubility of barium sulphate in 0.05 M in Barium chloride solution. The $K_{sp}$ of $BaSO_4=1.0 \times 10^{-10}$.
(m)What is the minimum amount of water required to dissolve 1g of calcium sulphate at 298K? $K_{sp}\left(CaSO_4\right)=9.1 \times{10}^{-6}$.
(n)Which of the following is not a Lewis Acid
(i) $BF_3$
(ii)$FeCL_3$
(iii) $SiF_4$
(iv) $C_2H_4$

Question 2
What is a common-ion effect?

Question 3
Give two uses of common-ion effect.

Question 4
What is Henderson-Hasselbalch equation?

Question 5
Calculate the molar solubility of $Ni(OH)_2$ in 10 M NaoH. The ionic product of $Ni(OH)_2$ is $2.0 \times 10^{-15}$

Question 6
The values of Ksp of two sparingly soluble salts $Ni(OH)_2$ and AgCN are $2.0 \times 10^{-15}$ and $6 \times 10^{-17}$ respectively. Which salt is more soluble? Explain.

Question 7
The solubility product constant of ${\rm Ag}_2CrO_4$ and AgBr are $5.0 \times 10^{-13}$ respectively. Calculate and ratio of the.molarities of their saturated solution.

Question 8
Will AgCl be more soluble in pur water or aqueous NaCl solution and why?

Question 9
The pKa of acetic acid and pKb of ammonium hydroxide are 7.76 and 4.75 respectively. Calculate the pH of ammonium acetate solution.

Question 10
Predict if the solutions of the following salts are neutral, acidic of basic:
NaCl,KBr, NaCN,${\rm NH}_4{\rm NO}_3$,$NaNO_2$ and KF

Question 11
What will be the decreasing order of basic strength of the following conjugate bases?
${\rm OH}^-$,${\rm RO}^-$,${\rm CH}_2C{\rm OO}^-$,${\rm Cl}^-$.

Question 12
Arrange the following in increasing order of pH.
${\rm KNO}_3\left(aq\right)$,${\rm CH}_3COONa\left(aq\right)$,${\rm NH}_4Cl\left(aq\right)$,$C_6H_5COONH_4\left(aq\right)$.

Question 13
Why is it essential to add dil. HCl before proceeding to test for the metals for the II group?

## Numericals

Question 14
Calculate [H+] when
(i) pH = 6.83
(ii) pH = 7.38
(iii) pH = 6.4

Question 15
Equal volumes of 0.002 M solutions of sodium chloride and silver nitrate are mixed together. Will its lead to precipitation of $AgCl(K_{sp})=10^{-10}$?

Question 16
Calculate the pH of a solution formed by mixing equal volumes of two solutions A and B of a strong acid having pH=6 and pH=4 respectively.

Question 17
The solubility product of $Al(OH)_3$ is $2.7 \times {10}^{-11}$. Calculate its solubility in g/L and also find out pH of this solution (Atomic mass of Al=27 u).

Question 18
Which of the following will produce a buffer solution when mixed in equal volumes?
(i) 0.1 $mol/dm^3$ ${\rm NH}_4OH$ and 0.1 $mol/dm^3$ HCl
(ii) 0.05 $mol/dm^3$ ${\rm NH}_4OH$ and 0.1 $mol/dm^3$ HCl
(iii) 0.1 $mol/dm^3$ ${\rm NH}_4OH$ and 0.05 $mol/dm^3$ HCl
(iv) 0.1 $mol/dm^3$ ${\rm CH}_4COONa$ and 0.1 $mol/dm^3$ NaOH

Question 19
Two gram of TiOH dissolved in water to give 2 litre soln. 204 = Ti; O = 16 gm; H = 1 gm. Give pH of the solution.

Question 20
0.3 g of Ca(OH)2 gives 500 ml of sol. Give pH of the solution.

Question 21
$FeO (s) + CO (g) \rightleftharpoons FeO + O_2 (g)$
Kp = 0.265 atm at 1050 K
Initial pressure : pCO2 = 0.8, pCO = 1.4
Find the equilbrium pressure of CO & CO2

Question 22
In the following reaction if initially 10 moles of PCl5 are taken which are 5% dissociated after reaching the equilibrium. Give the value of Equilibrium constant.

Question 23
$2 NOCl (g) \rightleftharpoons 2NO (g) + Cl2 (g)$
$K_p = 1.8 \times\ {10}^{-2}$ at 500 K

Question 24
The value of Kp for the reaction,
$CO2 (g) + C (s) \rightleftharpoons 2CO (g)$
is 3.0 at 1000 K. If initially pCO2 = 0.48 bar and PCO = 0 bar and pure graphite is present, calculate the equilibrium partial pressures of CO and CO2.