Multiple Choice Questions with Answer & Solutions of Acids, Bases and Salts
1. When zinc reacts with sodium hydroxide, the products formed are :
(A) Zinc hydroxide and sodium.
(B) Sodium zincate and water.
(C) Sodium zincate and hydrogen.
(D) Sodium zincate and oxygen
Solution
Sol. Zn + 2NaOH → Na2 ZnO2 + H2↑ï€
2. Calcium hydroxide (slaked lime) is used in :
(A) Plastics and dyes
(B) Fertilizers
(C) Antacid
(D) White washing
Solution
Sol. Ca(OH)2 use in white washing.
3. Which of the following is not a strong base?
(A) NaOH
(B) NH4OH
(C) KOH
(D) Ba(OH)2
Solution
Sol. NH4OH is weak base.
4. Which indicator does not changes its colour in basic conditions?
(A) Litmus
(B) Methyl orange
(C) Phenolphthalein
(D) Turmeric solution
Solution
Sol. Methyl orange give red colour in acidic solution.
5. The hydrogen atoms of an acid, which can be partially or completely replaced by an atom or a group of atoms are called :
(A) Basic hydrogen
(B) Replaceable hydrogen
(C) Acidic hydrogen
(D) Both (B) and (C)
Solution
Sol. Acid have replaceable basic or acidic hydrogen ion.
6. What is the basicity of H3PO2?
(A) 0
(B) 1
(C) 2
(D) 3
Solution
Sol. H3PO2 gives only one H+ ion in water so its basicity is one.
7. Which of the following does not displace hydrogen from dilute acids?
(A) Copper
(B) Sodium
(C) Magnesium
(D) Zinc
Solution
Sol. Copper is less reactive than hydrogen so it do not displace hydrogen gas from acid.
8. In one molecule of acetic acid, 4 hydrogen atoms are present, then basicity of acetic acid is :
(A) 1
(B) 2
(C) 3
(D) 4
Solution
Sol. CH3COOH have only one replaceable hydrogen atom.
9. The effect of water insoluble bases on phenolphthalein indicator is :
(A) Solution will turn from colourless to pink
(B) Solution will turn from pink to colourless
(C) No effect on the phenolphthalein indicator
(D) Solution will turn from colourless to red
Solution
Sol. They do not give colour change.
10. A blue litmus paper was first dipped in dil. HCl and then in dil. NaOH solution. It was observed that the colour of the litmus paper :
(A) Changed to red
(B) Changed first to red and then to blue
(C) Changed blue to colourless
(D) Remained blue in both the solution
Solution
Sol. Acid turns red while base turns in to blue.
11. Which of the following base is used in refining of petroleum :
(A) Fe(OH)3
(B) NaOH
(C) Al(OH)3
(D) NH4OH
Solution
Sol. NaOH use in refining of petroleum.
12. 8 gm NaOH is dissolved in one litre of solution, it’s molarity is: (atomic mass of Na = 23, O = 16, H = 1)
(A) 0.8 M
(B) 0.4 M
(C) 0.2 M
(D) 0.4 M
Solution
Sol. M = \frac{{\text{w}}}{{{\text{Molecular weight }}}} × \frac{{\text{1}}}{{{\text{V(in litre)}}}}  Â
= \frac{{\text{8}}}{{{\text{40}}}} \times \frac{1}{1} = 0.2\,\,M
13. The molarity of H2SO4 solution having pH value equal to 5 is:
(A) 5 × 10–5
(B) 5 × 10–6
(C) 5 × 10–7
(D) 5 × 10–4
Solution
Sol. pH = 5
N = M × valency
N = 10–5
M = \frac{{{\text{1}}{{\text{0}}^{{\text{--5}}}}}}{2} = 5 \times {10^{-6}}
14. 10–2 mole of KOH is dissolved in 10 litres of water. The pH of the solution is :
(A) 12
(B) 2
(C) 3
(D) 11
Solution
Sol. [OH–] = \frac{{{{10}^{-2}}}}{{10}} = {10^{-3}}Â
pOH = 3, pH = 11
15. When 4 gm of NaOH is dissolved in ten litre of solution, the pH is :
(A) 6
(B) 12
(C) 18
(D) 24
Solution
Sol. M = \frac{{\text{4}}}{{{\text{40}}}} \times \frac{1}{{10}} = {10^{-2}}Â
pOH = 2
pH = 14 – 2 = 12
16. If a solution has a pOH value of 14 at 25° C, H+ concentration should be :
(A) 0
(B) 10
(C) 1
(D) None of these
Solution
Sol. pOH = 14
17. pH of a 10–3 M NaCl solution (aq) at 25°C is :
(A) 7
(B) 11
(C) 3
(D) None of these
Solution
Sol. 10–3 M NaCl have pH = 7
18. Normality of a solution is defined as :
(A) Number of gram eq. /volume of solution in litre
(B) Number of eq./volume of solvent in litre
(C) Number of mole/mass of solvent in kg
(D) Number of mole/mass of solution in kg
Solution
Sol. N = \frac{{{\text{Number of gm eq}}{\text{.}}}}{{{\text{Volume}}\,\,{\text{of}}\,{\text{solution in litre}}}}
19. Number of gm equivalent present in 5 gm of oxalic acid (H2C2O4) are :
(A) 0.45
(B) 0.055
(C) 1.5
(D) 2.25
Solution
Sol. Number of gm equivalent = \frac{{\text{W}}}{{\text{E}}} = \frac{5}{{90}} = 0.055
20. The phenomenon of loss of water of crystallization in the molecule is known as :
(A) effervescence
(B) deliquescence
(C) efflorescence
(D) phosphorescence
Solution
Sol. phenomenon of loss of water of crystallization in the molecule is known as efflorescence. For example
CaSO4 ⋅ 2H2O → CaSO4 + 2H2O
21. What is brine solution :
(A) Hot concentrated solution of Sodium hydroxide
(B) Cold concentrated solution of Sodium chloride
(C) Hot concentrated solution of ammonia
(D) Cold concentrated solution of CaCO3
Solution
Sol. 30% cold concerted NaCl → Brine solution
22. Ammonical brine is :
(A) CaCl2 + NH3 + H2O
(B) CaCO3 + NH3 + H2O
(C) NaCl + NH3 + H2O
(D) CaCl2 + H2O + NaCl
Solution
Sol. Ammonical brine is mixture of NaCl + NH3 + H2O.
23. Which of the following correctly represents the molecular formula of washing soda :
(A) Na2CO3
(B) Na2CO3â‹…H2O
(C) Na2CO2.5H2O
(D) Na2CO3.10H2O
Solution
Sol. Chemical formula of washing soda = Na2CO3â‹…10H2O
24. Plaster of Paris is obtained :
(A) by adding water to Calcium sulphate
(B) by adding Sulphuric acid to Calcium hydroxide
(C) by heating gypsum to a very high temperature
(D) by heating gypsum to 100 °C
Solution
Sol.
25. The bleaching action of bleaching powder (CaOCl2) is due to :
(A) Ca present
(B) Oxygen present
(C) Cl2 present
(D) All of these
Solution
Sol. Bleaching action due to presence of Cl2.