Question

Which of the following statements is correct for the reaction:
$\mathrm{Al}+\mathrm{HCl}\to {\mathrm{AlCl}}_3+H_2$
(Given, the atomic mass of Al is 27 g)

[0.8 mark]

• A. The reaction equation follows the law of conservation of mass.
• B. If 27 g of Al combines with 36.5 g of HCl, it will produce 133.5 g of $AlC{l}_3$ and 2 g of $H_2$
  
• C. If 54 g of Al combines with 219 g of HCl, it will produce 267 g of $AlC{l}_3$ and 6 g of $H_2$.
• D. The given reaction is an example of a combination reaction.

Answer 1

The correct option is C If 54 g of Al combines with 219 g of HCl, it will produce 267 g of $AlC{l}_3$ and 6 g of $H_2$.

We can observe that the number of chlorine and hydrogen atoms on the reactant and product sides is not equal. Thus, the given reaction is not balanced. Thus, it does not follow the law of conservation of mass.
Balance chemical reaction:$2\mathrm{Al}+6\mathrm{HCl}\to 2{\mathrm{AlCl}}_3+3H_2$
The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction. Thus, the total mass of reactants should be equal to the total mass of products.
Thus, option B is incorrect, while option C obeys the law of conservation of mass and is correct.
Further, the given reaction is an example of a single displacement reaction.