$20 \, mL$ of $0.02 \, M \, K_2Cr_2O_7$ solution is used for the titration of $10 \, mL$ of $Fe^{2+}$ solution in the acidic medium. The molarity of $Fe^{2+}$ solution is ........... $\times 10^{-2} \, M$ (Nearest Integer).

If zinc pieces are added to yellow $FeCl_3$ solution,it turns to very light green. It is because

When $SO_2$ is bubbled into an acidic $KMnO_4$ solution,decolorization of the purple solution takes place along with the formation of a manganese compound $X$. Under neutral conditions,compound $X$ reacts with $KMnO_4$ in the presence of zinc oxide to give another manganese compound $Y$. The oxidation states of manganese in compounds $X$ and $Y$,respectively,are

Whenever a reaction between an oxidising agent and a reducing agent is carried out,a compound of lower oxidation state is formed if the reducing agent is in excess and a compound of higher oxidation state is formed if the oxidising agent is in excess. Justify this statement giving three illustrations.

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 reactions does not involve either oxidation or reduction?
$I. \ 2Cs + 2H_2O \to 2CsOH + H_2$
$II. \ 2CuI_2 \to 2CuI + I_2$
$III. \ NH_4Br + KOH \to KBr + NH_3 + H_2O$
$IV. \ 4KCN + Fe(CN)_2 \to K_4[Fe(CN)_6]$