Question

Which of the following statement(s) is/are true regarding nitric acid?

• A. It is a colourless liquid
• B. $HN{O}_3$ exists as a ​planar molecule​ in gaseous state.
• C. It has a boiling point of 231.4 K
• D. On exposure to light, it turns slightly brown

Answer 1

Answer: (A), (B), (D)

On exposure to light, it turns slightly brown

The physical properties of nitric acid are :-
1. The impure acid is yellow in colour.
2. It has boiling point 355.6 K and Freezing point is 231.4 K.
3. It has a corrosive action on skin and procuces painful blisters
4. It is a colourless liquid.
5. $HN{O}_3$ exists as a ​planar molecule​ in gaseous state.
6. On exposure to light, it turns slightly brown because of slight decomposition into $N{O}_2$ and $O_2$.​
$4HN{O}_3\to 4N{O}_2+O_2+2H_{2}O$​

Hence, (a), (b) and (d) are true.