Aqua regia is a mixture containing 50 per cent concentrated HCL and 70 per cent concentrated HNo3 in the ratio 1 : 3 respectively. Aqua regia is to be formed with 15 l of HCl of 80 percent concentration and 56 l of HNO3 of 90 per cent concentration by adding water as a diluting agent. Another mixture ’X’ having 40 percent concentrated HCL and 30 percent concentrated H2SO4 in the ratio 5 : 7 respectively is added to the Aqua regia to form a solution of 111 l. Find the ratio of HCL to water in the solution. Only water is used as a diluting agent  Choices:  A) 3 : 8  B) 4 : 7  C) 1 : 3  D) 2 : 5  E) 5 : 2
80 % concentrated HCL is to be diluted to form a 50% concentrated HCL solution.   The quantity of water to be added to the l5 l solution is i.e 5:3   Thus, (3/5) X 15 = 9   9 litres of water is added to HCL solution Similarly 16 l of water is added to 90%   concentrated solution of HNO3 to dilute it to 70% concentration.   The total quantity of HCL and HNO3 solutions are 24 l and 72 l respectively and that of the   aqua regia formed is 96 I and that of water in it is 33.6 l   The quantity of mixture ’X’ is 11 I - 96 = 15.   In the mixture X, the quantity of HCL is [(5/12) X 0.6 + (7/12) X 0.7] X 15=(0.25 + 0.41) X 15 = 9.91.   The required ratio is (12 + 2.5)/(33.6 + 9.9) = 14.5/43.5 = 1/3   ANSWER:1 : 3
<result>C</result>
Aqua regia is a mixture containing 50 per cent concentrated HCL and 70 per cent concentrated HNo3 in the ratio 1 : 3 respectively. Aqua regia is to be formed with 15 l of HCl of 80 percent concentration and 56 l of HNO3 of 90 per cent concentration by adding water as a diluting agent. Another mixture ’X’ having 40 percent concentrated HCL and 30 percent concentrated H2SO4 in the ratio 5 : 7 respectively is added to the Aqua regia to form a solution of 111 l. Find the ratio of HCL to water in the solution. Only water is used as a diluting agent