How many moles of $H_2O_2$ are required to decolorize $1$ mole of $KMnO_4$ (in $.5$)?

$5 \, M$ solution of $H_2SO_4$ is diluted from $1 \, L$ to $10 \, L$. What is the normality of the solution in $N$?

How many grams of a dibasic acid (molar mass $= 200$) are present in $100 \, mL$ of its aqueous solution to make its strength $0.1 \, N$ (decinormal)?

At constant temperature and pressure,the change in volume when $80\%\, 100\, mL$ of phosgene $(COCl_2)$ decomposes into $CO$ and $Cl_2$ is an increase of ............... $mL$.

Calculate the concentration of nitric acid in moles per litre in a sample which has a density of $1.41 \, g \, mL^{-1}$ and the mass percent of nitric acid in it is $69 \%$.

$7.8 \ g$ of a compound having molecular formula $C_6H_6$,on reacting with $CH_3COCl / AlCl_3$ gives $8.4 \ g$ of a product which has molecular formula $C_8H_8O$. Calculate the percentage yield of the product $C_8H_8O$. (Given atomic weights of $H$,$C$ and $O$ respectively are $1$,$12$ and $16$) (in $\%$)