The reagent 'X' used in the following reaction to obtain a good yield of the product is:
\( HI \)
Step 1: Understanding the Reaction Type
- The reaction involves the conversion of an alcohol to an alkyl iodide.
- The preferred method for this transformation is using potassium iodide (\( KI \)) in the presence of a strong acid.
Step 2: Choosing the Suitable Acidic Medium
1. Use of \( H_2SO_4 \) (Sulfuric Acid):
- Sulfuric acid oxidizes iodide ions (\( I^- \)) to molecular iodine (\( I_2 \)), reducing the availability of \( I^- \) needed for substitution.
- This results in a poor yield.
2. Use of \( H_3PO_4 \) (Phosphoric Acid, 95\% concentration):
- Unlike sulfuric acid, phosphoric acid does not oxidize \( I^- \), leading to a better yield of alkyl iodide.
- The reaction mechanism involves protonation of the hydroxyl group, making it a better leaving group, followed by nucleophilic substitution by \( I^- \).
Step 3: Evaluating the Given Options
- Option (1): Incorrect, as sulfuric acid leads to poor yield due to oxidation of \( I^- \).
- Option (2): Correct, as \( KI, 95\% \ H_3PO_4 \) provides the best yield of alkyl iodide.
- Option (3): Incorrect, as sodium iodide (\( NaI \)) with zinc chloride (\( ZnCl_2 \)) is used for Lucas test, not for alkyl iodide preparation.
- Option (4): Incorrect, as pure hydriodic acid (\( HI \)) is not typically used due to instability and side reactions.
Thus, the correct answer is
Option (2).
The \( C-O-H \) bond angle in A is \( X \) and \( C-O-C \) bond angle in B is \( Y \). What are X and Y?
IUPAC name of the following compound is:
List I | List II | ||
(P) | ![]() | (1) | ![]() |
(Q) | ![]() | (2) | ![]() |
(R) | ![]() | (3) | ![]() |
(S) | ![]() | (4) | ![]() |
(5) | ![]() |
List I | List II | ||
(P) | ![]() | (1) | ![]() |
(Q) | ![]() | (2) | ![]() |
(R) | ![]() | (3) | ![]() |
(S) | ![]() | (4) | ![]() |
(5) | ![]() |
Given the vectors:
\[ \mathbf{a} = \mathbf{i} + 2\mathbf{j} + \mathbf{k} \]
\[ \mathbf{b} = 3(\mathbf{i} - \mathbf{j} + \mathbf{k}) = 3\mathbf{i} - 3\mathbf{j} + 3\mathbf{k} \]
where
\[ \mathbf{a} \times \mathbf{c} = \mathbf{b} \]
\[ \mathbf{a} \cdot \mathbf{x} = 3 \]
Find:
\[ \mathbf{a} \cdot (\mathbf{x} \times \mathbf{b} - \mathbf{c}) \]
If three numbers are randomly selected from the set \( \{1,2,3,\dots,50\} \), then the probability that they are in arithmetic progression is:
A student has to write the words ABILITY, PROBABILITY, FACILITY, MOBILITY. He wrote one word and erased all the letters in it except two consecutive letters. If 'LI' is left after erasing then the probability that the boy wrote the word PROBABILITY is: \