Structural and Physical Properties of Carbonyls

Q.

What is steric hindrance & steric effects?

Q.

Arrange the following compounds in increasing order of their boiling points.

CH₃CHO, CH₃CH₂OH, CH₃OCH₃, CH₃CH₂CH₃

Q.

Decreasing order of reactivity of alkyl halide is: RCl, RI, RBr.

Q. An organic compound X with molecular formula $C_5{H}_{10}O$ gives test with phenyl hydrazine but gives a negative response to iodoform test and Tollen’s test. It produces n-pentane on reduction. The compound could be

1. pentanal
2. pentan-2-one
3. pentan-3-one
4. amyl alcohol

Q. Which of the following exhibit electromeric effect?

1. Alkanes
2. Aldehydes
3. Alkyl halides
4. Alkyl amines

Q.

Iodoform test is not given by:

1. 2-Pentanone

2. Ethanol

3. Ethanal

4. 3-pentanone

Q. Compound '$A$' (molecular formula $C_3{H}_{8}O$ is treated with acidified potassium dichromate to form a product '$B$' (molecular formula $C_3{H}_{6}O$). '$B$' forms a shining silver mirror on warming with ammoniacal silver nitrate. '$B$' when treated with an aqueous solution of $H_{2}NCONHN{H}_2$ and sodium acetate gives a product '$C$'. Identify the structure of '$C$'.

1. $C{H}_{3}C{H}_{2}CH=NNHCON{H}_2$
2. 
3. 
4. $C{H}_{3}C{H}_{2}OH+NCONHN{H}_2$

Q. Among the following compounds, which one has maximum boiling point ?

1. Propionic acid
2. Ethyl methyl ketone
3. n-butyraldehyde
4. n-pentane

Q. Dipole moment of $C{O}_2$ is zero which implies that

1. Carbon has no polar bond
2. Carbon has bond moments of zero value
   
3. CO₂ is a linear molecule
4. Carbon and oxygen have equal electronegativities

Q. The boiling points of aldehydes and ketones lie in between alkanes and alcohols of comparable masses because:

1. aldehydes and ketones are non-polar
2. alkanes are non-polar and aldehydes and ketones contain polar group and lower alcohols have H-bonding
3. alkanes are held together by weak van der Waals’ forces (being non-polar), aldehydes and ketones contain polar and held together by strong dipole-dipole attraction and lower alcohols have H-bonding, which is stronger than dipole-dipole attraction
4. alkanes are polar

Q. An organic compound $X$ on treatment with pyridinium chlorochromate (PCC) in $C{H}_{2}C{l}_2$ gives compound $Y.$ Compound $Y$ reacts with $I_2/NaOH$ to form iodoform. The compound $X$ is:

1. $C{H}_{3}C{H}_{2}OH$
2. $C{H}_{3}CHO$
3. 
4. $C{H}_{3}COOH$

Q. For the given compounds:
(a) m-methoxybenzoic acid
(b) benzoic acid
(c) p-methoxybenzoic acid
Choose the correct option(s):

1. m-Methoxybenzoic acid is more acidic than p-methoxybenzoic acid
2. m-Methoxybenzoic acid is the least acidic
3. Benzoic acid is more acidic than p-methoxybenzoic acid
4. Benzoic acid is the most acidic

Q.

Why is ${\mathrm{PCl}}_5$ Lewis acid?

Q.

Why do alkyl groups show positive inductive effect?

Q.

What is hydrophilic moiety?

Q. The decreasing order of solubility of methanal (A), propanaldehyde (B), benzaldehyde (C) and acetophenone (D):

1. A > B > C > D
2. D > C > B > A
3. D > A > B > C
4. B > A > C > D

Q. An organic compound X with molecular formula $C_5{H}_{10}O$ gives test with phenyl hydrazine but gives a negative response to iodoform test and Tollen’s test. It produces n-pentane on reduction. The compound could be

1. pentan-2-one
2. pentanal
3. pentan-3-one
4. amyl alcohol

Q. $B$ reacts with hydroxyl amine but does not give Tollens' test. Identify $A$ and $B.$
$\underset{\left(C_4{H}_{8}C{l}_2\right)}{A}\underset{373K}{\overset{\text{Hydrolysis}}{\to }}\underset{\left(C_4{H}_{8}O\right)}{B}$

1. 1, 1-Dichlorobutane and 2-Butanone
2. 2, 2-Dichlorobutane and Butan-2-one
3. 2, 2-Dichlorobutane and Butanal
4. 1, 1-Dichlorobutane and Butanal

Q. $C{H}_{3}C{H}_{2}OH$ can be converted into $C{H}_{3}CHO$ by:

1. catalytic hydrogenation
2. treatement with $LiAl{H}_4$
3. treatment with pyridinium chlorochromate
4. treatement with $KMn{O}_4$

Q.

Why does CH_{​​​​​3} show +I effect and behave as an electron donor?

Q. The common characteristic of cis-2-butene and trans-2-butene is:

1. solubility
2. heat of hydrogenation
3. melting point and boiling point
4. product of hydrogenation

Q.

If water molecule is linear

A it would have high boiling point

B it would be highly reactive

C its dipole moment would be zero

D it will be highly ionic

Q. HCHO and HCOOH are distinguished by treating with:

1. NaHCO₃
2. Fehling’s solution
3. Benedict solution
4. Tollen’s reagent

Q. 17. The vapour pressure of a solution in benzene is 722mm and that of solvent is 760mm. What is the Molality of the solution

Q.

Which of the following compounds is soluble in ether?

1. Oils and fats

2. Water

3. NaCl

4. PCl₅

Q. What is formed when a primary alcohol undergoes oxidation in presence of $PCC$.

1. Aldehyde
2. Ketone
3. Alkene
4. Carboxylic acid

Q. Arrange in the compounds in their decreasing order of boiling point.

1. Methoxyethane
2. Acetone
3. n-Butanol
4. Butane

Q.

Observe the following structures and pick up the correct statement ?

1. Carbonyl carbon of I is more electrophilic than that of II

2. Carbonyl carbon of I is less electrophilic than that of II

3. Carbonyl carbon of both structures have equal electrophilic character
   

4. It depends upon the complete structure of the compound

Q. most acidic hydrogen is present in? 1 . CH3-CO-CH2-CO-O-CH3 2 .CH3-O-CO-CH2-CO-O-CH3 3. CH3-CO-CH2-CO-CH3 4. CH3-CO-CH2-CH3

Q. Which one is the most acidic in nature --- formic acid, acetic acid , propanoic acid and phenol??