2➤
Write the solubility product of sparingly soluble salt Bi₂S3.
=> Ans: Bi-S 2B +38)
3➤
What is the pOH if the hydrogen ion concentration in solution is
=> 1x 10¹ mol dm? Ans: pH = -log[H₂O'] = -log[1 x 10']=3 pH + pOH = 14
pOH = 14-pH=14-3=11 4. Write the relationship between molar solubility
(S) and solubility product (K₁p) for CaF₂ Ans: CaF2C+2) x = 1, y = 2
Kpx'y' S (1) (2) S¹2=4S³
4➤
Give any one example of salt derived from weak acid and weak base.
=> Ans: Ammonium acetate, CH,COONH₂
5➤
Write the formula to calculate pH of buffer solution. Ans
=> The formula to calculate the pH of acidic buffer solution is: pH =
pk, + log0 [Acid]
6➤
Label the one conjugate acid-base pair in the following reaction. + H₂OOH
+ HCO;
=> Ans: CO +H,O, — OH + HCO, Base Acid, t Conjugate acid-base
pair
7➤ Calculate the pOH of 10* M of HCI.
=> cannot be effect. [H] 10 M but less than 10 M. H H₂O + OH a (10 + a)
K[H] [OH]=(10* + a) a a² + ax 10-10-14-0 Solving above quadratic
equation, we get a=0.95 x 10 [H] = 10 +0.95 x 107-1.05 x 10 M pH =
-log[H] = -log[1.05 x 10"] -6.9788 pOH = 14-6.9788=7.0212 = 7
8➤ What is an ionic equilibrium?
=> Ans. Ionic equilibrium: The equilibrium between ions and unionised
molecules of an electrolyte in solution is called an ionic equilibrium.
CH₂COOH) CH₂COO(g) + H)
9➤
Write a reaction in which water acts as a base.
=> Ans. H₂O) + HCl = H₂O + CI Base, Acid, Acid, Base, Since water
accepts a proton, it acts as a base.
10➤
If pH of a solution is 2, what is the concentration of OH in the solution?
=> pH + pOH = 14 POH=14-pH=14-2=12 [OH-] = Antilog -12.0=1 x 10-12
M.
11➤
How does pH of pure water vary with temperature? Explain.
=> Ans. Since the increase in temperature increases dissociation of
water, its pH decreases.
12➤
What is a nature of a solution of a salt of weak acid and strong base?
=> Ans. The solution of a salt of weak acid and strong base is basic in
nature. For example, a solution of NaCN.
13➤ What a buffer solution consists of?
=> Ans. (i) An acidic buffer solution consists of a weak acid and its
salt of a strong base. For example, (CH₂COOH +CH,COONa). (ii) A basic
buffer solution consists of a weak base and its salt of a strong acid.
For example, (NH₂OH-NH₂C1).
14➤
Mention the common ion present in the following solutions: (a) A solution
containing CH₂COOH and CH₂COONa (b) A solution containing NH OH and
NH,CI.
=> Ans. (a) A solution containing CH₂COOH and CH,COONa has a 64 common
ion CH,COO. (b) A solution containing NH OH and NH₂Cl has a common ion
NH.
15➤ What is common ion?
=> Common ion: An ion common to two electrolytes is called common ion.
This is generally applicable to a mixture of a strong and a weak
electrolyte. For example, a solution containing weak electrolyte CH₂COOH
and strong electrolyte salt CH,COONa. CH,COONa—CH COO +Na*;
CH₂COOH=CH₂COO + H+ Hence, CH₂COOH and CH₂COONa have a common ion
CH,COO™.
