$A\,\xrightarrow{{H{g^{2 + }}\,/\,{H^ + }}}B\,\xrightarrow{{NaB{H_4}}}C\,\xrightarrow[{conc.\,\,HCl}]{{ZnC{l_2}}}$ Turbidity within $5$ minutes.
$‘A’$ શું હશે?