Which of the following equations is written incorrectly?

$CaCO_3 + 2HCl \to CaCl_2 + CO_2 + H_2O$ ; In this chemical reaction,what will be the amount of calcium chloride formed when $10 \ g$ of calcium carbonate and $400 \ mL$ of $0.25 \ M$ $HCl$ are used? (Atomic masses: $Ca=40, C=12, O=16, H=1, Cl=35.5$)

At $100\,^oC$,a $1.5\,L$ vessel contains $0.4\,g$ of $O_2$ and $0.06\,g$ of $H_2$. $(a)$ What is the total pressure in the vessel? $(b)$ If the mixture reacts to form water at $100\,^oC$,which gas will remain in the vessel? What will be their partial pressures (in $,atm$)? $(R = 0.0821\, L\,atm\,mol^{-1}\,K^{-1})$.

$20 \ mL$ of $0.1 \ M$ $HCl$ is added to $30 \ mL$ of $0.1 \ M$ $NaOH$. To this solution,an extra $50 \ mL$ of water was added. What is the molarity of the final solution formed (in $M$)?

How many moles of $P_4$ can be produced by reaction of $0.10 \ mol$ $Ca_5(PO_4)_3F$,$0.36 \ mol$ $SiO_2$,and $0.90 \ mol$ $C$ according to the following reaction?
$4Ca_5(PO_4)_3F + 18SiO_2 + 30C \to 3P_4 + 2CaF_2 + 18CaSiO_3 + 30CO$

$1.0 \ g$ of $Mg$ is burnt with $0.28 \ g$ of $O_2$ in a closed vessel. Which reactant is left in excess and how much?