The drain cleaner Drainex contains small bits of aluminium which reacts with caustic soda to produce hydrogen. What volume of dihydrogen at ${{20}^{0}}C$ and at one bar will be released when 0.15 gram of aluminium reacts?

Hint: Sodium Hydroxide is also known as caustic soda. Dihydrogen here is referred to as the hydrogen molecule with two hydrogen atoms in it. Di- means two.

Step by step answer:
When drain cleaner Drainex contains small bits of aluminium reacts with caustic soda, the reaction can be written as:
$\text{2A}{{\text{l}}_{\left( s \right)}}\text{ + 2NaO}{{\text{H}}_{\left( \text{aq} \right)}}\text{ + 2}{{\text{H}}_{2}}{{\text{O}}_{\left( \text{l} \right)}}\xrightarrow{{}}2\text{NaAl}{{\text{O}}_{{{2}_{\left( \text{aq} \right)}}}}\text{ + 3}{{\text{H}}_{{{2}_{\left( \text{g} \right)}}}}$
By the above equation, we can determine that 2 moles of Aluminium release 3 moles of Hydrogen gas.
Moles of Aluminum produced
 $\text{= }\dfrac{0.15\text{g}}{27}\text{ = }5.56\times {{10}^{-3}}\text{ moles}$
Therefore, Moles of ${{\text{H}}_{\text{2}}}$ produced
 $\text{= }\dfrac{3}{2}\times 5.56\times {{10}^{-3}}\text{ moles}$
$=\text{ 8}\text{.33 }\times \text{ 1}{{\text{0}}^{-3}}\text{ moles}$
Therefore, we can determine that the volume of
${{\text{H}}_{\text{2}}}\text{ = }\dfrac{\text{nRT}}{\text{P}}$
$\text{= }\dfrac{8.33\text{ }\times \text{ 1}{{\text{0}}^{-3}}\times \text{ 0}\text{.0831 }\times \text{ 293}}{1}$
$\text{= }0.203\text{ litres}$
Therefore, the volume of dihydrogen released by the reaction is 0.203 litres.

Note: Here are some properties that we should be knowing about the drain cleaners:
A dream cleaner is a chemical compound that unlocks sewer pipes or blocked wastewater drains. The term may also refer to a mechanical device such as a plumber’s snake, drain auger, toilet plunger or similar device. Occasionally the term is applied to a plumber or other individual who performs the drain cleaning and hygiene.
There are alkaline drain openers primarily containing sodium hydroxide and some may contain potassium hydroxide. They appear in liquid or solid form. Solid formulations of corrosive alkaline drain cleaners are composed of a caustic substance, aluminium particles and additives. These additives often include wetting agents such as alkyl aryl sulfonates, but the exact nature of these additives and not known for commercial drain cleaners as they are regarded as trade secrets that make each train cleaner unique with the brand.