If the density of methanol is $0.793 \ kg \ L^{-1}$,what volume is needed to prepare $2.5 \ L$ of a $0.25 \ M$ solution (in $mL$)?

$60 \ mL$ $NaOH$ solution is required for complete neutralization of $0.98 \ g$ orthophosphoric acid. The concentration of $NaOH$ solution is ............. $M$.

$A$ $1.84 \, mg$ sample of polyhydric alcoholic compound '$X$' of molar mass $92.0 \, g/mol$ gave $1.344 \, mL$ of $H_2$ gas at $STP$. The number of alcoholic hydrogens present in compound '$X$' is $.....$

$7.8 \ g$ 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 $\%$)

Combustion of glucose $(C_6H_{12}O_6)$ produces $CO_2$ and water. The amount of oxygen (in $g$) required for the complete combustion of $900 \ g$ of glucose is:
[Molar mass of glucose in $g \ mol^{-1} = 180$]

The ratio of amounts of $H_2S$ needed to precipitate all the metal ions from $100 \ mL$ of $1 \ M$ $AgNO_3$ and $100 \ mL$ of $1 \ M$ $CuSO_4$ is