jee main chemistry important questions | Hydrocarbons jee main questions FREE

Q 1 :

Given below are two statements : [2025]

Statement (I): Neopentane forms only one monosubstituted derivative.

Statement (II): Melting point of neopentane is higher than $n$ -pentane.

In the light of the above statements, choose the most appropriate answer from the options given below :

Statement I is correct but Statement II is incorrect
Both Statement I and Statement II are correct
Both Statement I and Statement II are incorrect
Statement I is incorrect but Statement II is correct

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(2)

Statement I:

Statement II: Melting point of neopentane = –16.4°C, Melting point of n-pentane = –129.8°C

Q 2 :

Isomeric hydrocarbons → negative Baeyer’s test (Molecular formula $C_{9} H_{12}$ )

The total number of isomers from above with four different non-aliphatic substitution sites is _____. [2025]

(2)

Q 3 :

80 mL of a hydrocarbon on mixing with 264 mL of oxygen in a closed U-tube undergoes complete combustion. The residual gases after cooling to 273 K occupy 224 mL. When the system is treated with KOH solution, the volume decreases to 64 mL. The formula of the hydrocarbon is: [2026]

$C_{4} H_{10}$
$C_{2} H_{6}$
$C_{2} H_{2}$
$C_{2} H_{4}$

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(3)

$C_{x} H_{y} {}_{(g)}+ (x + \frac{y}{4}) O_{2} {}_{(g)}⟶ x C O_{2} {}_{(g)}+ \frac{y}{2} H_{2} O_{(ℓ)}$

$\begin{matrix} t = 0 & 80 & 264 & 0 & - \\ t = t_{final} & - & 264 - 80 (x + \frac{y}{4}) & 80 x & - \end{matrix}$

$264 - 80 (x + \frac{y}{4}) + 80 x = 224$

$264 - \frac{80 y}{4} = 224$

$40 = \frac{80 y}{4} \Rightarrow y = 2$

$264 - 80 (x + \frac{y}{4}) = 64$

$264 - 80 (x + \frac{1}{2}) = 64$

$264 - 80 x - 40 = 64$

$x = 2$

Q 4 :

Consider the following reaction sequence

The percentage of nitrogen in product ‘T’ formed is ______ %. (Nearest integer)
(Given molar mass in g ${mol}^{- 1}$ : H : 1, C : 12, N : 14, O : 16) [2026]

(20)

$Mol. wt = 6 \times 12 + (6 \times 1) + (2 \times 14) + (2 \times 16)$ $= 138$

$% N = \frac{28}{138} \times 100 = 20.29 %$

Q 5 :

Consider the following reaction of benzene:

In compound (Q), the percentage of oxygen is ______ %. (Nearest integer) [2026]

(10)

$Molecular mass of Q is = 157$

$% of oxygen in product 'Q' is = \frac{16}{157} \times 100 = 10.19 %$

Q 6 :

3, 3-Dimethyl-2-butanol cannot be prepared by :

Choose the correct answer from the options given below : [2026]

B Only
B and E Only
B and C Only
B, C and E Only

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(2)

Q 7 :

Consider the following reaction sequence

Compound (y) develops characteristic colour with neutral ${FeCl}_{3}$ solution.

Identify the INCORRECT statement from the following for the above sequence. [2026]

Both compounds x and y will dissolve in NaOH.
Compound y will dissolve in ${NaHCO}_{3}$ and evolve a gas.
Compound x is more acidic than compound y.
Both compounds x and y will burn with sooty flame.

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(3)

Topic Question Set

Q 1 :

Given below are two statements : [2025]

Statement (I): Neopentane forms only one monosubstituted derivative.

Statement (II): Melting point of neopentane is higher than $n$ -pentane.

In the light of the above statements, choose the most appropriate answer from the options given below :

Q 2 :

Isomeric hydrocarbons → negative Baeyer’s test (Molecular formula $C_{9} H_{12}$ )

The total number of isomers from above with four different non-aliphatic substitution sites is _____. [2025]

Q 3 :

80 mL of a hydrocarbon on mixing with 264 mL of oxygen in a closed U-tube undergoes complete combustion. The residual gases after cooling to 273 K occupy 224 mL. When the system is treated with KOH solution, the volume decreases to 64 mL. The formula of the hydrocarbon is: [2026]

Q 4 :

Consider the following reaction sequence

The percentage of nitrogen in product ‘T’ formed is ______ %. (Nearest integer)
(Given molar mass in g ${mol}^{- 1}$ : H : 1, C : 12, N : 14, O : 16) [2026]

Q 5 :

Consider the following reaction of benzene:

In compound (Q), the percentage of oxygen is ______ %. (Nearest integer) [2026]

Q 6 :

3, 3-Dimethyl-2-butanol cannot be prepared by :

Choose the correct answer from the options given below : [2026]

Q 7 :

Consider the following reaction sequence

Compound (y) develops characteristic colour with neutral ${FeCl}_{3}$ solution.

Identify the INCORRECT statement from the following for the above sequence. [2026]

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Topic Question Set

Q 1 : Given below are two statements : [2025] Statement (I): Neopentane forms only one monosubstituted derivative. Statement (II): Melting point of neopentane is higher than n-pentane. In the light of the above statements, choose the most appropriate answer from the options given below :

Q 2 : Isomeric hydrocarbons → negative Baeyer’s test (Molecular formula C9H12) The total number of isomers from above with four different non-aliphatic substitution sites is _____. [2025]

Q 3 : 80 mL of a hydrocarbon on mixing with 264 mL of oxygen in a closed U-tube undergoes complete combustion. The residual gases after cooling to 273 K occupy 224 mL. When the system is treated with KOH solution, the volume decreases to 64 mL. The formula of the hydrocarbon is: [2026]

Q 4 : Consider the following reaction sequence The percentage of nitrogen in product ‘T’ formed is ______ %. (Nearest integer) (Given molar mass in g mol-1: H : 1, C : 12, N : 14, O : 16) [2026]

Q 5 : Consider the following reaction of benzene: In compound (Q), the percentage of oxygen is ______ %. (Nearest integer) [2026]

Q 6 : 3, 3-Dimethyl-2-butanol cannot be prepared by : Choose the correct answer from the options given below : [2026]

Q 7 : Consider the following reaction sequence Compound (y) develops characteristic colour with neutral FeCl3 solution. Identify the INCORRECT statement from the following for the above sequence. [2026]

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Q 1 :

Given below are two statements : [2025]

Statement (I): Neopentane forms only one monosubstituted derivative.

Statement (II): Melting point of neopentane is higher than $n$ -pentane.

In the light of the above statements, choose the most appropriate answer from the options given below :

Q 2 :

Isomeric hydrocarbons → negative Baeyer’s test (Molecular formula $C_{9} H_{12}$ )

The total number of isomers from above with four different non-aliphatic substitution sites is _____. [2025]

Q 3 :

80 mL of a hydrocarbon on mixing with 264 mL of oxygen in a closed U-tube undergoes complete combustion. The residual gases after cooling to 273 K occupy 224 mL. When the system is treated with KOH solution, the volume decreases to 64 mL. The formula of the hydrocarbon is: [2026]

Q 4 :

Consider the following reaction sequence

The percentage of nitrogen in product ‘T’ formed is ______ %. (Nearest integer)
(Given molar mass in g ${mol}^{- 1}$ : H : 1, C : 12, N : 14, O : 16) [2026]

Q 5 :

Consider the following reaction of benzene:

In compound (Q), the percentage of oxygen is ______ %. (Nearest integer) [2026]

Q 6 :

3, 3-Dimethyl-2-butanol cannot be prepared by :

Choose the correct answer from the options given below : [2026]

Q 7 :

Consider the following reaction sequence

Compound (y) develops characteristic colour with neutral ${FeCl}_{3}$ solution.

Identify the INCORRECT statement from the following for the above sequence. [2026]