(a)The reaction will be: Zn+2NaOH(aq)→Na2ZnO2+H2 Since zinc is more reactive so it liberates hydrogen gas in the aqueous solution of NaOH. (b) The reaction will be: HCOOH
373K
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Conc.H2SO4
H2O+CO Formic acid liberated CO and water molecule on heating. (c)Methane liberated hydrogen gas on reaction with water molecule at 1270 K. CH4(g)+H2O(g)
1270K
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Ni
CH3OH+H2 (d)Zinc will also liberate hydrogen gas in acidic medium. Zn+2H+(aq)→Zn2++H2 (e)Carbon also liberates hydrogen gas in aqueous medium at 1270 K. C+H2O