Hướng dẫn:

${{n}_{NaOH}}={{V}_{NaOH}}.{{C}_{{{M}_{NaOH}}}}=0,2.0,5=0,1\left( mol \right)$

$C{{l}_{2}}+2NaOH\to NaCl+NaClO+{{H}_{2}}O$

            0.1                   0,05                     (mol)

Theo phương trình ta có:

${{n}_{NaClO}}=\frac{{{n}_{NaOH}}}{2}=\frac{0,1}{2}=0,05\left( mol \right)$

$\Rightarrow {{m}_{NaClO}}={{n}_{NaClO}}.{{M}_{NaClO}}=0,05.74,5=3,725\left( g \right)$

Chọn đáp án C