(c)
212,
25. How much pure alcohol should be added to 600
ml. of a 15% solution to make its strength 32%
Answers
Answer:
150 ml alcohol must be added to make 32 % strength of the solution.
Step-by-step explanation:
Let x ml of pure alcohol be added to 600 ml of a 15% solution to make it strength 32%. Here, 15% solution means that there is 15 ml pure alcohol in a solution of 100 ml.
Now, quantity of alcohol in 100 ml solution=15ml
Therefore,quantity of alcohol in 1 ml solution = 15/100ml
quantity of alcohol in 600 ml solution = 15/100×600ml
=90ml
Total quantity of the solution =(600+x) ml
total quantity of alcohol in (600+x) ml solution= (90+x) ml
therefore, quantity of alcohol in 1 ml = 90+x/600+x ml
quantity of alcohol in 100 ml = 90+x/600+x×100ml
So, strength of the solution= (90+x/600+x)×100 percent
But, the strength of the solution is given as 32%.
therefore, 90+x/600+x×100 = 32
=) 100(90+x) = 32(600+x)
=) 9000+ 100x = 19200+32x
=) 100x- 32x = 19200-9000
=) 68x = 10200
=) x = 10200/68
=) x = 150.