$Na_2S_2O_3$ reacts with moist $Cl_2$ to form $Na_2SO_4$,$HCl$,and $X$. Which one of the following is $X$?

The equivalent weight of $K_2Cr_2O_7$ in an acidic medium is...... (Molecular weight $= M$)

After balancing the reaction $Cu + HNO_3 \rightarrow Cu(NO_3)_2 + NO_2 + H_2O$ in an acidic medium,the number of nitrogen atoms,the number of water molecules,and the net charge on the product side are respectively:

In an alkaline medium,$ClO_2$ oxidizes $H_2O_2$ to $O_2$ and is reduced to $Cl^-$. How many moles of $H_2O_2$ will be oxidized by $1$ mole of $ClO_2$?

The oxidation state of chromium in the final product formed in the reaction between $KI$ and acidified $K_{2}Cr_{2}O_{7}$ solution is:

Balance the redox reaction where $Fe^{+2}$ in an acidic medium reduces $Cr_2O_7^{-2}$ ion to $Cr^{+3}$ ion,while $Fe^{+2}$ itself is oxidized to $Fe^{+3}$.