If salt $Q$ undergoes a redox reaction with $H_2S$ in an acidic medium,then which of the following species cannot be a possible product?

In neutral or faintly alkaline medium,$MnO_4^{-}$ oxidizes $I^{-}$ to iodate. What is the number of moles of $KMnO_4$ required to completely convert $1 \ L$ of $0.5 \ M \ KI$ to iodate?

Assign $A, B, C, D$ from the given type of reaction.
$K_2Cr_2O_7 + 2NaOH \longrightarrow 2K_2CrO_4 + H_2O$
Identify the nature of the product $CrO_4^{2-}$ formed in the reaction.

Which of the following reduction products of $NO_3^-$ involves the maximum number of moles of electrons taken up per mole of $NO_3^-$?

What volume of $O_{2(g)}$ measured at $1 \ atm$ and $273 \ K$ will be formed by the action of $100 \ mL$ of $0.5 \ N \ KMnO_4$ on hydrogen peroxide in an acidic solution? The skeleton equation for the reaction is: $KMnO_4 + H_2SO_4 + H_2O_2 \to K_2SO_4 + MnSO_4 + O_2 + H_2O$.

Observe the following reactions:
$(i)$ $2 KClO_{3(s)} \xrightarrow{\Delta} 2 KCl_{(s)} + 3 O_{2(g)}$
$(ii)$ $2 H_2O_{2(aq)} \xrightarrow{\Delta} 2 H_2O_{(l)} + O_{2(g)}$
$(iii)$ $AgNO_{3(aq)} + KCl_{(aq)} \longrightarrow AgCl_{(s)} + KNO_{3(aq)}$
$(iv)$ $2 Na_{(s)} + \frac{1}{2} O_{2(g)} \longrightarrow Na_2O_{(s)}$
The number of redox reactions in this list is