Question

Lime $\left( {CaO} \right)$ dissolved in muriatic acid $\left( {HCl} \right)$ to form calcium chloride$\left( {CaC{l_2}} \right)$ and water $\left( {{H_2}O} \right)$.
(a) X moles $HCl$ would be required to dissolve $8.8$ moles of $CaO$.
(b) Y moles of ${H_2}O$ would be formed. Determine the value of X and Y.
A. $X - 2$, $Y - 8.8$.
B. $X - 2$, $Y - 8.0$.
C. $X - 3$, $Y - 8.0$.
D. $X - 17.6$, $Y - 8.8$.

Answer 1

We know molar ratio relates the amount of moles of any two substances in the chemical reaction. The numbers in conversion factors are the coefficients of the substance in the chemical reaction.
Consider a reaction,
${N_2}\left( g \right) + 3{H_2}\left( g \right)\xrightarrow{{}}2N{H_3}\left( g \right)$
The mole ratio relating the ammonia and nitrogen is given as $\dfrac{{2\,\,mole\,N{H_3}}}{{1\,mole\,{N_2}}}$.

Complete step by step answer:
A balanced chemical equation tells the number of moles of reactants and the number of moles of product.
First write the balanced chemical equation of the reaction.
$CaO\left( s \right) + 2HCl\left( {aq} \right)\xrightarrow{{}}CaC{l_2}\left( {aq} \right) + {H_2}O\left( l \right)$
Given,
The number of moles of calcium oxide is $8.8\,mole$.
To calculate the X moles $HCl$ required to dissolve $CaO$ , write the mole ratio relating the hydrochloric acid and calcium oxide.
The mole ratio is $\dfrac{{2\,mol\,HCl}}{{1\,mole\,of\,CaO}}$
Now, multiply the number of moles of calcium oxide with the molar ratio.
$8.8\,mol\,CaO \times \dfrac{{2\,mol\,HCl}}{{1\,mole\,of\,CaO}} = 17.6\,mol$
The number of moles of hydrochloric acid, $X = 17.6\,mole$.
To calculate the Y moles ${H_2}O$ formed, write the mole ratio relating the hydrochloric acid and calcium oxide.
The mole ratio is $\dfrac{{1\,mol\,{H_2}O}}{{1\,mole\,of\,CaO}}$
Now, multiply the number of moles of calcium oxide with the molar ratio.
$8.8\,mol\,CaO \times \dfrac{{1\,mol\,{H_2}O}}{{1\,mole\,of\,CaO}} = 8.8\,mol$
The number of moles of water, $Y = 8.8\,mole$

Therefore option (D) is correct.

Note:
We can use the coefficients in the balanced equation to write the molar ratio that places the unwanted unit in the denominator so that the unit gets canceled. Also we have to know that the muriatic acid is one of the names of a corrosive strong acid, the hydrochloric acid. They are also known as salt spirits or acidum salis. "Muriatic" means "salt or brine-related". For muriatic acid, the chemical formula is HCl. The acid is widely available in delivery stores at home.