$5.75 \ mg$ of sodium vapour is converted to sodium ion. If the ionisation energy of sodium is $490 \ kJ \ mol^{-1}$ and atomic weight is $23 \ g \ mol^{-1}$, the amount of energy needed for this conversion will be (in $kJ$)

What mass of $95 \%$ pure $CaCO_3$ will be required to neutralise $50 \ mL$ of $0.5 \ M \ HCl$ solution according to the following reaction? (In $g$)
$CaCO_{3(s)} + 2HCl_{(aq)} \rightarrow CaCl_{2(aq)} + CO_{2(g)} + H_2O_{(l)}$
[Calculate up to the second decimal place]

The density of $2 \ M$ aqueous solution of $NaOH$ is $1.28 \ g \ cm^{-3}.$ The molality of the solution is $... \ m$ [Given that molecular mass of $NaOH = 40 \ g \ mol^{-1}$]

$1.25 \ g$ of a solid dibasic acid is completely neutralized by $25 \ mL$ of $0.25 \ M$ $Ba(OH)_2$ solution. The molecular mass of the acid is:

Gastric juice contains about $3.0 \ g$ of $HCl$ per liter. If a person produces about $2.6 \ liters$ of gastric juice per day,find the number of antacid tablets required to neutralize all the $HCl$ produced. Consider each antacid tablet contains $400 \ mg$ of $Al(OH)_3$. [Given,atomic masses: $Al=27, O=16, H=1, Cl=35.5$]

How many grams of $HCl$ are required to prepare $1500 \, mL$ of $0.1 \, N \, HCl$ aqueous solution?