Question

$CaC{O}_3+2HCl\to CaC{l}_2+H_{2}O+C{O}_2$

The mass of calcium chloride formed when 2.5 g of calcium carbonate is dissolved in excess of hydrochloric acid is:

• A. 1.39 g
• B. 2.78 g
• C. 5.18 g
• D. 17.8 g

Answer 1

The correct option is B 2.78 g

CaCO₃ + 2HCl -----> CaCl₂ + H₂O + CO₂.
2.5g? g
Mass of CaCO₃= 40+12+3(16)=52+ 48= 100.
Molar mass of CaCO₃=100g.
Mass of CaCl₂= 40 + 2(35.5)= 40+ 71= 111.
Molar mass of CaCl₂=111g.
Mass of CaCO₃ (g) Mass of CaCl₂ (g)
For 100g of $CaC{O}_3$, 111g of CaCl_2$ is formed.
let for 2.5g of $CaC{O}_3$, $x$ g of $CaC{l}_2$ is formed.
Thus, by cross multiplication,

$x=111\times 2.5/100=2.775g=2.78g$.