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?
The reaction of aluminium with caustic soda can be represented as:
2Al+2NaOH+2H2O→2NaAlO2+3H22×27g 3×22400 mL
At STP (273.15 K and 1 atm), 54 g (2 × 27 g) of Al gives 3 × 22400 mL of H2..
∴0.15 g Al gives 3×22400×0.1554mL of H2 i.e.,186.67 mLofH2.
At STP,
p1=1 atmv1=186.67 mLT1=273.15 K
Let the volume of dihydrogen be V2atp2=0.987 atm (since 1 bar = 0.987 atm) and T2=20∘C=(273.15+20)K=293.15K.
Now,
p1V1T1=p2V12T2⇒V2p1V1T2p2T1=1×186.67×293.150.987×273.15=202.98 mL=203 mL
Therefore, 203 mL of dihydrogen will be released.