The conversion of sugar $C_{12}H_{22}O_{11} \to CO_2$ is

$A$ sulphur molecule is converted into a sulphide ion when it:

Observe the following reactions:
$I$. $2H_2O_{(l)} + 2Na_{(s)} \rightarrow 2NaOH_{(aq)} + H_{2(g)}$
$II$. $2H_2O_{(l)} + 2F_{2(g)} \rightarrow 4H^{+}_{(aq)} + 4F^{-}_{(aq)} + O_{2(g)}$
Identify the correct statement from the following:

Addition of iron filings to $CuSO_4$ solution causes the precipitation of $Cu$ due to the:

Identify the redox couples involved in the following reactions:
$(a) \ Cu + Zn^{+2} \to Cu^{+2} + Zn$
$(b) \ Mg + Fe^{+2} \to Mg^{+2} + Fe$
$(c) \ Br_{2} + 2Cl^{-} \to Cl_{2} + 2Br^{-}$
$(d) \ Fe + Cd^{+2} \to Cd + Fe^{+2}$

When zinc is added to $CuSO_4$,copper is precipitated due to: