General Science MCQ – 30 (Chemistry)

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1. Find the pH of a solution when 0.01M HCI and 0.1 M NaOH are mixed in equal volumes?
(A) 12.65
(B) 1.04
(C) 7.0
(D) 2.0

2. Which of the following aqueous solution will be the best conductor of electricity?
(A) NH3
(B) CH3COOH
(C) HCI
(D) C6H12O6

3. In 0.10 M aqueous solution of pyridine (C5H5N), find the percentage of pyridine that for pyridinium ion (C5H5N+H)(kb for C5H5N = 1.7 x 10-9)?
(A) 1.6%
(B) 0.77%
(C) 0.0060%
(D) 0.013%

4. Find the equilibrium constant of the reaction, if the equilibrium constant for the following reaction are given
N2 + 3H2 ⇔ 2NH3 – K1
N2 + O2 ⇔ 2NH – K2
N2 + ½ O2 ⇔ N2O – K3?
(A) K2K3K/K1
(B) K1K33/K2
(C) K2K33/K
(D) K23K3/K1

5. The highest pH will be recorded for which of the following solutions if they are equimolar?
(A) AICI3
(B) BaCI2
(C) BeCI2
(D) LiCI

6. The equilibrium constant is 278 for the reaction
2SO2(g) + O2(g) ⇔ 2SO3(g)
At the same temperature, what will be the equilibrium constant for the following reaction
SO3(g) ⇔ SO2(g) + 1/2 O2(g) ?
(A) 6 x 10 -2
(B) 1.8 x 10-3
(C) 1.3 x 10-5
(D) 3.6 x 10-5

7. What will be the pH of a buffer solution having an equal concentration of B- and HB (kb for B-)?
(A) 7
(B) 4
(C) 10
(D) 6

8. Find the increase in equilibrium concentration of Fe3+ ions if OH- ions concentration decrease to ¼ in the following reaction
Fe(OH)3(s)⇔Fe3+(aq.)+3OH−(aq.)?
(A) 8 times
(B) 16 times
(C) 4 times
(D) 64 times

9. On increasing the concentration of reactions in a reversible reaction, then equilibrium constant will?
(A) Depend on the concentration
(B) Increase
(C) Unchanged
(D) Decrease

10. Find the conjugate acid of NH2-?
(A) NH3
(B) NH4OH
(C) NH+
(D) NH2-