Question

The specific gravity of a solution is 1.8, having 62% by weight of acid. It is to be diluted to specific gravity of 1.2. What volume of water should be added to 100 ml of this solution ?​

Answer 1

Answer:

$Let\:to\:100\:ml\:of\:given\:acid\:solution\:\\(\:sp.\:gr.\:1.8\:)\:x\:ml\:of\:water\:is\:added.\\\\∴\:The\:total\:vol.\:of\:resulting\:solutin\:\\=\:(\:100\:+\:x)\:ml\\\\∴\:the\:total\:weight\:of\:resulting\:\\solution\:=\:(100 + x) 1.2 gm\\\\weight\:of\:acid\:present\:in\:the\:given\:acid\:solution\:\\(per\:100\:ml)\:=\:100\:*1.8\:*\:0.62\\\\∴\:the\:amount\:of\:water\:present\:in\:100\:ml\:of\:given\:\\acid\:solution\:=\:1.8\:*100\:*0.38\\∴\:total\:wt.\:of\:acid\:present\:in\:the\:diluted\:solution\:\\=\:(100\:+\:x) 1.2\:-\:X\:-\:180\:*\:0.38= 1.8 * 100*0.62\\∴\:120\:+0.2x\:=\:180\:or\:x\:=\:300\\\\∴\:To\:lower\:sp.\:gravity\:of\:the\:given\:acid\:solution\:to\:1.2,\:we\:are\:\\to\:add\:300\:ml\:of\:water\:per\:100\:ml\:of\:acid\:solution\:(sp.\:gr.\:1.2)$