Question

In the reaction :
$2A{l}_{\left(6\right)}+6HCl\left(aq\right)\to 2Al{}^{3+}\left(aq\right)+6Cl{}^{-}\left(aq\right)+3H_2\left(g\right)$

Choose the correct options for above chemical reaction.

• A. $6$ L $HC{l}_{\left(aq\right)}$ is consumed for every $3$ L $H_{2\left(g\right)}$ produced
• B. $33.6$ L $H_2\left(g\right)$ is produced regardless of temperature and pressure for every mole $Al$ that reacts
• C. $67.2$ L $H_2\left(g\right)$ at STP is produced for every mole $Al$ that reacts
• D. $11.2$ L $H_2\left(g\right)$ at STP is produced for every mole $HCl\left(aq\right)$ consumed

Answer 1

Answer: (B), (D)

The correct options are
B $33.6$ L $H_2\left(g\right)$ is produced regardless of temperature and pressure for every mole $Al$ that reacts
D $11.2$ L $H_2\left(g\right)$ at STP is produced for every mole $HCl\left(aq\right)$ consumed

In option A, the conditions of temperature and pressure are not mentioned.
Hence, the number of moles of hydrogen cannot be determined.

Hence, the option, $6$ L $HC{l}_{(}aq)$ is consumed for every $3$ L $H_2\left(g\right)$ produced, cannot be correct.
Thus, option A is incorrect.

For options, B and C, $2$ moles of $Al$ reacts with $3$ moles of hydrogen.

Hence, $1$ mole of $Al$ will react with $1.5$ moles of hydrogen.
At STP, $1.5$ moles of hydrogen will occupy a volume of $1.5\times 22.4=33.6L$

Thus, $33.6$ L of hydrogen gas is produced at standard temperature and pressure only for every mole $Al$ that reacts.
Hence, option B is correct and option C is incorrect.

In the case of option D, from the balanced chemical equation, it can be seen that $6$ moles of $HCl$ reacts with $3$ moles of hydrogen.
Hence, $1$ mole of $HCl$ will react with $\frac{3}{6}=0.5$ moles of hydrogen.

At STP, $1$ mole of hydrogen corresponds to $22.4$ L.

Hence, $0.5$ moles of hydrogen will correspond to $\frac{22.4}{2}=11.2L$.

Thus, $11.2$ L of hydrogen gas at STP is produced for every mole of $HCl$ consumed.

Thus, option $D$ is correct.