$10 \, L$ solution of urea contains $240 \, g$ urea. The active mass of urea will be

If $8 \ g$ of $NaOH$ is dissolved in $1 \ L$ of solution,its molarity will be ....... $M$.

How many grams of dibasic acid (mol. wt. $200$) should be present in $100 \ mL$ of its aqueous solution to give decinormal strength?

$7.8 \ g$ 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 $\%$)

How many grams of $CaCO_3$ must be decomposed to produce $20 \ L$ of $CO_2$ at $750 \ torr$ and $27 \ ^\circ C$?

One third litre of $x \ M \ K_2Cr_2O_7$ is required to completely oxidise $2 \ L$ of $0.1 \ M$ ferrous ammonium sulphate in acidic medium. What is $x$?