Sun October 14, 2012 By: Vinit

1)2.50g sample of sodium bicarbonate when strongly heated gave 300cm^3 of CO2 measured 27C and 760mm pressure. Calculate the percentage purity of the sample? 2)10ml of liquid carbon disulphide(sp.gravity 2.63)is burnt in oxygen.Find the volume of the resulting gases measured at S.T.P? 3)The drain cleaner, Drainex contains small bits of Al which reacts with caustic soda to produce H2. what volume of H2 at 20C and one Bar pressure will be released when 0.15g Al reacts?

Expert Reply
Tue April 23, 2013

2NaHCO3 = Na2CO3 + CO2 +H2O

168g 22400ml

22400 ml CO2 obtained by = 168 g of NaHCO3

300 ml CO2 obtained by = 168 x 300 /22400

=2.25 g

Percentage purity = 2.25 x 100 /2.5

= 90%

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