How many moles of $H_2O$ are liberated when one mole of hydrated $MgCl_2$ is heated?

Excess of $NaOH\, (aq)$ was added to $100\, mL$ of $FeCl_3\, (aq)$ resulting in $2.14\, g$ of $Fe(OH)_3$. The molarity of $FeCl_3\, (aq)$ is (Given molar mass of $Fe=56\, g\, mol^{-1}$ and molar mass of $Cl=35.5\, g\, mol^{-1}$) (in $, M$)

$LiOH$ reacts with $CO_2$ to form $Li_2CO_3$ (atomic mass of $Li = 7$). The amount of $CO_2$ (in $g$) consumed by $1\, g$ of $LiOH$ is closest to $....\, g$

Calcium carbonate reacts with aqueous $HCl$ to give $CaCl_{2}$ and $CO_{2}$ according to the reaction,
$CaCO_{3(s)} + 2HCl_{(aq)} \rightarrow CaCl_{2(aq)} + CO_{2(g)} + H_{2}O_{(l)}$
What mass of $CaCO_{3}$ is required to react completely with $25 \ mL$ of $0.75 \ M$ $HCl$ (in $g$)?

Which of the following is required to neutralize $1 \ L$ of $1 \ N \ NaOH$?

Volume of $0.1 \, M$ $H_2SO_4$ required to neutralize $30 \, mL$ of $0.2 \, N$ $NaOH$ is......$mL$