Question

The drain cleaner, Drainex contains small bits of aluminum which react with caustic soda to produce dihydrogen. What volume of dihydrogen at 20 °C and one bar will be released when 0.15g of aluminum reacts? 

Answer 1

Aluminium reacts with caustic soda in accordance with the reaction

The reaction of aluminium with caustic soda can be represented as:

Therefore volume of hydrogen at STP released when 0.15g of Al reactsv

=0.15 x 3 x 22.4 /54 = 187ml

Now P₁ = 1 bar,

P₂ = 1 bar

T₁ = 273 K

T₂ = 20 + 273 = 293 K

V₁ = 187 ml

V₂ = x

When pressure is held constant,then

V₂ = P₁ V₁ T₂ / P₂ T₁

OR

x = 1 X 187 X 293 / 0.987 X 273

= 201 ml

Therefore, 201 mL of dihydrogen will be released

Answer 2

The reaction of aluminium with caustic soda can be represented as: