Question

Which of the following gases on dissolution in water make the solution acidic?

• A. CO
• B. $C{O}_2$
• C. $S{O}_3$
• D. $P{H}_3$

Answer 1

Answer: (B), (C)

The correct options are
B $C{O}_2$
C $S{O}_3$

Reaction of the given compounds with water is as follows:

1. $CO+H_{2}O\rightleftharpoons C{O}_2+H_2$
   
2. $C{O}_2+H_{2}O\rightleftharpoons H_{2}C{O}_3$ (Acid)
3. $S{O}_3+H_{2}O\rightleftharpoons H_{2}S{O}_4$) (Acid)
4. when pure $P{H}_3$ does not react with water