$20.0 \ g$ of a magnesium carbonate sample decomposes on heating to give carbon dioxide and $6.0 \ g$ magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample? (Atomic weight of $Mg = 24$)

Calculate the volume of $H_2$ gas kept at $STP$ if it contains as many $H$ atoms as in $98 \ g$ of $H_3PO_4$. (Atomic mass of $P = 31 \ u$) (in $L$)

$5 \, L$ of a gaseous mixture of ethane and propane are burnt to produce total $11 \, L$ of $CO_2$. Volume percent of $C_2H_6$ in the initial mixture is

The number of moles of hydrogen molecules required to produce $20$ moles of ammonia through Haber's process is

Phosphoric acid $(H_3PO_4)$ is a tribasic acid and one of its salts is sodium dihydrogen phosphate $(NaH_2PO_4)$. What volume of $1 \ M$ $NaOH$ solution should be added to $12 \ g$ of sodium dihydrogen phosphate (mol. wt. $120$) to exactly convert it into trisodium phosphate $(Na_3PO_4)$? (Answer in $mL$)

To neutralise $20 \, mL$ of $M/10$ sodium hydroxide,the volume of $M/20$ hydrochloric acid required is .............. $mL$