InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
Mark the correct order of decreasing acid strength of the following compounds. A. `V gt IV gt II gt I gt III`B. `II gt IV gt I gt III gt V`C. `IV gt V gt III gt II gt I`D. `V gt IV gt III gt II gt I` |
|
Answer» Correct Answer - B Presence of electron withdrawing group on phenols, increases its acidic stength. So, both compounds i.e., p-nitrophenol (II) and m-nitrophenol (IV) are stronger acid than (I). If this `-NO_(2)` group is present at p-position, then it exerts both -I and -R effect but if it is present at meta position, then it exerts only -I effect. Therefore, p-nitrophenol is much stronger acid than m-nitrophenol. On the other hand, presence of electron releasing group on phenol, decreases its acidic strength. If `-OCH_(3)` group is present at meta position, it will not exert +R effect but exert -I effect. But, if it is present at para position, then it will exert +R effect. Therefore, m-methoxy phenol is more acidic than p-methoxy phenol. Hence, the correct option is (b). |
|