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Aldehydes, Ketones and Carboxylic Acids · Question 46

AIPMT 2012 (Mains)Multiple CorrectMedium📈 Topic in 12% papers+4−1
1

Which of the following compounds will give a yellow precipitate with iodine and alkali?

  1. Acetophenone
  2. Methyl acetate
  3. Acetamide
  4. 2-Hydroxypropane

Answer

(1) Acetophenone, (4) 2-Hydroxypropane

Solution

The yellow precipitate is iodoform (CHI3). The iodoform test is given by compounds containing CH3CO- attached to C or H (methyl ketones, acetaldehyde) and by alcohols with CH3CH(OH)- (which are oxidised to such carbonyl compounds).

(1) Acetophenone, C6H5COCH3 – a methyl ketone ⇒ gives CHI3.

(2) Methyl acetate, CH3COOCH3 – the CH3CO- group is attached to O (ester) ⇒ no iodoform.

(3) Acetamide, CH3CONH2 – CH3CO- attached to N (amide) ⇒ no iodoform.

(4) 2-Hydroxypropane (propan-2-ol), CH3CH(OH)CH3 – oxidised by I2/alkali to acetone ⇒ gives CHI3.

Answer: (1), (4)

AIPMT 2012 (Mains)

Keep practising — Aldehydes, Ketones and Carboxylic Acids

2

Consider the following reaction [figure] The product A is

  1. C6H5CHO
  2. C6H5OH
  3. C6H5COCH3
  4. C6H5Cl
AIPMT 2012 (Mains)
3

In the following sequence of reactions CH3-Br KCNA H3O+B [ether]LiAlH4C the end product (C) is

  1. acetone
  2. methane
  3. acetaldehyde
  4. ethyl alcohol
AIPMT 2012 (Prelims)
4

CH3CHO and C6H5CH2CHO can be distinguished chemically by

  1. Benedict's test
  2. Iodoform test
  3. Tollens' reagent test
  4. Fehling's solution test
AIPMT 2012 (Prelims)
5

The correct order of decreasing acid strength of trichloroacetic acid (A), trifluoroacetic acid (B), acetic acid (C) and formic acid (D) is

  1. B > A > D > C
  2. B > D > C > A
  3. A > B > C > D
  4. A > C > B > D
AIPMT 2012 (Prelims)
6

Predict the products in the given reaction. [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
AIPMT 2012 (Prelims)
7

Acetone is treated with excess of ethanol in the presence of hydrochloric acid. The product obtained is

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
AIPMT 2012 (Prelims)
8

The order of reactivity of phenyl magnesium bromide (PhMgBr) with the following compounds: [figure]

  1. III > II > I
  2. II > I > III
  3. I > III > II
  4. I > II > III
AIPMT 2011 (Mains)
9

Clemmensen reduction of a ketone is carried out in the presence of which of the following?

  1. Glycol with KOH
  2. Zn-Hg with HCl
  3. LiAlH4
  4. H2 and Pt as catalyst
AIPMT 2011 (Prelims)
10

Following compounds are given (i) CH3CH2OH (ii) CH3COCH3 (iii) CH3- CH3 |CHOH (iv) CH3OH Which of the above compound(s), on being warmed with iodine solution and NaOH, will give iodoform?

  1. (i), (iii) and (iv)
  2. Only (ii)
  3. (i), (ii) and (iii)
  4. (i) and (ii)
AIPMT 2010 (Mains)
11

Which one of the following compounds will be most readily dehydrated?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
AIPMT 2010 (Mains)

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