An orgonic compound on analysis is found to contain C=18.6% , H=1.55% , Cl=55.04% , and O=24.8%.Calculate its molecular formula?

2 answers

Your School SUBJECT seems to be CHEMISTRY.
Let me point out that the total adds up to 99.99; it should add to 100 but that probably won't make any difference in the answer.

Take 100 g sample which gives you
18.6 g C
1.55 g H
55.04 g Cl
24.8 g O

Convert to mols and I will estimate; you should recalculate each.
18.6/12 = about 1.6 C
1.55/1 = 1.55 H
55.04/35.5 = about 1.5
24.8/16 = 1.5

Now find the ratio of the elements to one another with the smallest being 1.00. The easy way to do that is to divide the smallest number by itself (thereby assuring it to be 1.00), then divide the other numbers by the same small number.
So the empirical formula is CHClO. Withe the information given the molecular formula cannot be calculated.