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← JEE Main 2017 · 9 Apr · Shift 1
ChemistrySingle correct+4 / -1Question 59 of 90

JEE Main 2017 · 9 Apr · Shift 1, Chemistry question 59

In the following reaction sequence :
I(CX3HX6ClX2)→KOH(aq)II→(ii) HX2O/HX+(i) CHX3MgBrIII→Anhy. ZnClX2 + Con. HClgives turbidity immediately\underset{(\ce{C3H6Cl2})}{\text{I}}\ce{->[KOH(aq)]}\text{II}\xrightarrow[\text{(ii) }\ce{H2O/H+}]{\text{(i) }\ce{CH3MgBr}}\text{III}\xrightarrow{\text{Anhy. }\ce{ZnCl2}\text{ + Con. HCl}}\text{gives turbidity immediately}
The compound I is :

Choose one option
Answer and worked solution

Official answer: D

Turbidity at once with the Lucas reagent means III is a tertiary alcohol. 2,2-Dichloropropane is hydrolysed by aqueous KOH (via the gem-diol) to acetone (II), and CHX3MgBr\ce{CH3MgBr} then gives tert-butyl alcohol (III). So I is CHX3−CClX2−CHX3\ce{CH3-CCl2-CH3}.