InterviewSolution
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InterviewSolution
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A mixture pf `H_(2) , N_(2)` and `O_(2)` occupying 100 ml underwent reaction so as to form `H_(2)O_(2)(l)` and `N_(2)H_(2)(g)` as the only products , causing the volume to contract by 60 ml. The remaining mixture was passed through pyrogallol causing a contraction of 10 ml . to the remaining mixture excess `H_(2)` was added and the above reaction was repeaped , causing a reduction in volume of 10 ml .(No other products are formed) What is the volume of `N_(20H_(2)(g)` formed in this reaction after adding excess of `H_(2)(g)`? |
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Answer» Correct Answer - 4 After first step reaction there exists excess O2 as evident by subsequent absorption by pyrogallol .. So H2 is not present there in excess after first step. After absorption of O2 the gas mixture should contain N2H2(g) and excess N2. This excess N2 is reacted with H2 added in excess to carry out 2nd step reaction according to the following equation N2 (g). + H2 (g) -> N2H2 (g) Where it is obvious that 1ml N2 reacts with 1ml H2 to produce 1ml N2H2(g) and contraction in volume will be 1ml. As the given contraction in volume is 10 ml the volume of N2H2 formed in 2nd step should be 10ml and the volume of N2 consumed will be 10 ml also. Now we will proceed to estimate the volume of N2H2 (g) produced in first phase. To do this let us consider x ml H2 goes to react with O2 and y ml with N2 . x ml H2 gas will combine with 0.5x ml O2 (g) to produce 0 ml H2O(l) and the contraction due to this reaction will be 1.5x ml Again following the equation N2 (g). + H2 (g) -> N2H2 (g) we can say, y ml H2 will require y ml N2 to react and will produce y ml N2H2 (g). The contraction in volume due to this is y ml So volume of N2 spent in first step will be y ml. Summing up we can say ,the composition of the mixture at first is as follows volume of H2=> (x+y)ml , volume of N2 => (y+10) ml and volume of O2=> (0.5x+10)ml So by the question we get (x+y)ml +(y+10) ml +(0.5x+10)ml = 100 ml =>1.5x +2y =80 ................(1) considering the total contraction we get 1.5x +y =60 ................(2) subtracting (2) from (1) we get y = 20 ml Hence total volume of N2H2 produced in two steps will be (10+20) ml = 30 ml |
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