$NaClO$ solution reacts with $H_2SO_3$ as,$NaClO + H_2SO_3 \to NaCl + H_2SO_4$. $A$ solution of $NaClO$ used in the above reaction contained $15 \ g$ of $NaClO$ per litre. The normality of the solution would be

The number of moles of $K_2Cr_2O_7$ reduced by $1 \ mol$ of $Sn^{+2}$ is:

When copper is heated with concentrated $HNO_3$,it produces:

Balance the following redox reactions by the ion-electron method:
$(a)$ $MnO_{4(aq)}^- + I_{(aq)}^- \to MnO_{2(s)} + I_{2(s)}$ (in basic solution)
$(b)$ $MnO_{4(aq)}^- + SO_{2(g)} \to Mn_{(aq)}^{2+} + HSO_{4(aq)}^-$ (in acidic solution)
$(c)$ $H_2O_{2(aq)} + Fe_{(aq)}^{2+} \to Fe_{(aq)}^{3+} + H_2O_{(l)}$ (in acidic solution)
$(d)$ $Cr_2O_7^{2-} + SO_{2(g)} \to Cr_{(aq)}^{3+} + SO_{4(aq)}^{2-}$ (in acidic solution)

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$(NH_4)_2Cr_2O_7 \xrightarrow{\Delta} N_2 \uparrow + Cr_2O_3 \downarrow + 4H_2O \uparrow$

$PbS + 4O_3 \,\to ?\,+\,4O_2$