Read the following paragraph and answer Q.17 and Q.18.
The reaction of compound P with CHX3MgBr (excess) in (CX2HX5)X2O followed by addition of HX2O gives Q. The compound Q on treatment with HX2SOX4 at 0∘C gives R. The reaction of R with CHX3COCl in the presence of anhydrous AlClX3 in CHX2ClX2 followed by treatment with HX2O produces compound S. [Et in compound P is ethyl group]
The product S is