`Zn` gives `H_(2)` gas with `H_(2)SO_(4)` and `HCl` but not with `HNO_(3)` because

Options

A. `Zn` acts as an oxidising agent when it reacts with `HNO_(3)`
B. `HNO_(3)` is weaker acid than `H_(2)SO_(4)` and `HCl`
C. In electrochemical series, `Zn` is above hydrogen
D. `NO_(3)^(Theta)` is reduced in preference to hydronium ion.

Answer

D

Explanation

Zinc gives `H_(2)` gas with dil. `H_(2)SO_(4)//HCl` but not with `HNO_(3)` because in `HNO_(3)`, `NO_(3)^(-)` ion is reduced and gives `NH_(4)^(+)`, `N_(2)O`, `NO` and `NO_(2)` (based upon the concentration of `HNO_(3)`)
`[Zn+2HNO_(3) rarr Zn(NO_(3))_(2)+2H]xx4`
( nearly `6%`)
`HNO_(3)+8H rarr NH_(3)+3H_(2)O`
`NH_(3)+HNO_(3) rarr NH_(4)NO_(3)`
`4Zn+10HNO_(3) rarr 4Zn(NO_(3))_(2)+NH_(4)NO_(3)+3H_(2)O`
`Zn` is on the top position of hydrogen in electronchemical series. So `Zn` displaces `H_(2)` from dilute `H_(2)SO_(4)` and `HCl` with liberation of `H_(2)`.