Question

Which of the following statement about hydrogen is incorrect ?

• A. Hydrogen never acts as cation in ionic salts
• B. Hydronium ion, $H_3O^+$ exists freely in solution
• C. Dihydrogen does not act as a reducing agent
• D. Hydrogen has three isotopes of which tritium is the most common

Answer 1

Answer: (C), (D)

Hydrogen exist as a hydride $\left( H ^{-}\right)$in ionic salt.
Most abundant form of hydrogen is protium.
Dihydrogen reduces some metal ions in aqueous solution and oxides of metals (less active than iron) into corresponding metals.
$H _2( g )+ Pd ^2+( aq ) \longrightarrow Pd ( s )+2 H ^{+}( aq )$
$yH _2( g )+ MxOy ( s ) \longrightarrow xM ( s )+ yH _2 O (\ell)$