1.

An acidic solution of Cu^(2+) salt containing 0.4 g of Cu^(2+) is electrolysed until all the copper is deposited. The electrolysis is continued for seven more minutes with the volume of solution kept at 100 ml and the current at 1.2 amp. Calculate the volume of gases evolved at NTP during the entire electrolysis.

Answer»

`O_2 = 99.79 ml, H_2 = 48.45 ml`
`O_2 = 87.91 ml , H_2 = 58.48 ml `
`O_2 = 99.79 ml , H_2 = 58.48 ml `
`O_2 = 100 ml , H_2 = 50 ml`

Solution :`aq. CuSO_4 to CU + (1)/(2) O_2 + H_2SO_4 , (W_1)/(E_1) =(W_2)/(E_2) implies (0.4)/(63.5//2) = (W_2)/(8) = 0.0504 xx 2 GM = 0.10072`
`V_(O_2)(1) = 2 xx (0.0504)/(2) xx 22.4 = 35.27 ml = 70.55 ml`
But ` aq. CuSO_4 ("prolonged")/("ELECTROLYSIS") H_2 + (1)/(2) O_2 = 70.55 mm`
` 2 xx 96500 "coul" to 22.4 ltrs " of " H_2 & 11.2 ltrs " or "O_2 , (1.2 xx 7 xx 60) " coul" to V_(H_2) =? & V_(O_2(2)) =?`
` V_(H_2) = (1.2 xx 7 xx 60 xx 22.4)/( 2 xx 96500) = 58.495 ml " of" H_2 , V_(O_2(2)) = (1.2 xx 7 xx 60 xx 11.2)/(2 xx 96500) = 29.248 ml`
` V_(O_2(1)) iff 70.55 ml , V_(O_2)(1) + (2) = 99.799 ml HO_2 , V_(H_2) = 58.5ml , V_(O_2) = 99.8 ml " of " O_2`


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