Q.
The drain cleaner, Drainex contains small bits of aluminium which react with caustic soda to produce dihydrogen. What volume of dihydrogen at 20 °C and one bar will be released when 0.15 g of aluminium reacts?
The reaction between aluminium and caustic soda is 2Al+2NaOH+2H2O→2NaAlO2+3H2 2×27=54g3×22.4L at STP ∴54g of Al produces H2 at STP=3×22.4L 0.15g of Al will produce H2 at STP =543×22.4×0.15=0.186L
At STP Given conditions P1=1atmP2=1bar=0.987atm V1=0.186LV2=? T1=273KT2=273+20=293K
Applying ideal gas equation, T1P1V1=T2P2V2 2731×0.1867=2930.987×V2 V2=0.987293×2731×0.1867=0.2030L=203mL