JAMB - Chemistry (1984 - No. 38)

At S. T. P how many litres of hydrogen can be obtained from the reaction of 500 cm\(^3\) of 0.5 M H\(_2\)SO\(_4\) with excess zinc metal?
(Gram molecular volume of H\(_2\) = 22.4 dm\(^3\))
22.4 dm 3
11 . 2 dm 3
6. 5 dm 3
5. 6 dm 3
0. 00 dm 3

Explanation

 Zn  + H\(_2\)SO\(_4\) →  ZnSO\(_4\)  +  H\(_2\)

 1mole  :  1mole

  n = \(\frac{CV}{1000}\)

  = \(\frac{{0.5}\times{500}}{1000}\)

  = 0.25 mole : 0.25 mole

 n = \(\frac{Volume}{Molar Volume}\)

 0.25 = \(\frac{V}{22.4}\)

 V = 0.25 x 22.4

 V = 5.6 dm\(^3\)

 

 

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