Q.66. Given below are two statements : Statement-I : Due to increase in van der Waals forces, the or

Q: What is the correct answer for JEE Main Chemistry Q66?

The correct answer is C. Statement I: Boiling points of alkyl halides increase with increasing molecular weight and surface area. The order of molecular weights is $CH_3CH_2CH_2I > CH_3CH_2I > CH_3I$. Therefore, the order of boiling points is $CH_3CH_2CH_2I > CH_3CH_2I > CH_3I$. This statement is true. Statement II: 1,4-dichlorobenzene (para-dichlorobenzene) is more symmetric than 1,2-dichlorobenzene (ortho-dichlorobenzen

Q: Q.66. Given below are two statements : Statement-I : Due to increase in van der Waals forces, the order of boiling points is . Statement-II: As [Figure: 1,4-dichlorobenzene] is more symmetric, its…

The correct answer is C. Statement I: Boiling points of alkyl halides increase with increasing molecular weight and surface area. The order of molecular weights is $CH_3CH_2CH_2I > CH_3CH_2I > CH_3I$. Therefore, the order of boiling points is $CH_3CH_2CH_2I > CH_3CH_2I > CH_3I$. This statement is true. Statement II: 1,4-dichlorobenzene (para-dichlorobenzene) is more symmetric than 1,2-dichlorobenzene (ortho-dichlorobenzen

Q: What are the options for this JEE Main Chemistry question?

A. Both Statement-I and Statement-II are true. · B. Both Statement-I and Statement-II are false. · C. Statement-I is true but Statement-II is false. · D. Statement-I is false but Statement-II is true.

Question

Q.66. Given below are two statements : Statement-I : Due to increase in van der Waals forces, the order of boiling points is . Statement-II: As [Figure: 1,4-dichlorobenzene] is more symmetric, its melting point is higher than [Figure: 1,2-dichlorobenzene] however [Figure: 1,4-dichlorobenzene] its boiling point is lower than [Figure: 1,2-dichlorobenzene]. In the light of the above statements, choose the correct answer from the options given below :

FirstInTest · Accepted Answer

Statement I: Boiling points of alkyl halides increase with increasing molecular weight and surface area. The order of molecular weights is $CH_3CH_2CH_2I > CH_3CH_2I > CH_3I$. Therefore, the order of boiling points is $CH_3CH_2CH_2I > CH_3CH_2I > CH_3I$. This statement is true. Statement II: 1,4-dichlorobenzene (para-dichlorobenzene) is more symmetric than 1,2-dichlorobenzene (ortho-dichlorobenzene) and 1,3-dichlorobenzene (meta-dichlorobenzene). Due to its symmetry, it packs more efficiently in the crystal lattice, leading to a higher melting point. However, 1,4-dichlorobenzene has a zero dipole moment ($\mu=0$) due to the cancellation of bond dipoles, while 1,2-dichlorobenzene has a non-zero dipole moment ($\mu 
e 0$). A higher dipole moment leads to stronger dipole-dipole interactions, which increases the boiling point. Therefore, 1,4-dichlorobenzene has a lower boiling point than 1,2-dichlorobenzene. This statement is true. Since both statements are true, the correct option should be (1). However, the provided answer is (3) Statement-I is true but Statement-II is false. Let's re-evaluate Statement II. The melting point of p-dichlorobenzene is higher than o-dichlorobenzene due to symmetry. The boiling point of p-dichlorobenzene is lower than o-dichlorobenzene because o-dichlorobenzene has a higher dipole moment leading to stronger intermolecular forces. So, Statement II as written is: "As p-dichlorobenzene is more symmetric, its melting point is higher than o-dichlorobenzene however p-dichlorobenzene its boiling point is lower than o-dichlorobenzene." This entire statement is correct. Therefore, both Statement I and Statement II are true. There seems to be a discrepancy between my analysis and the provided answer. Based on chemical principles, both statements are true. If the answer is (3), then Statement II must be false. But the components of Statement II (higher MP for para, lower BP for para) are both correct. Let's assume the provided answer (3) is correct and try to find a reason why Statement II would be false. Perhaps the comparison of boiling points is not always straightforward, but generally, para isomers have lower boiling points than ortho/meta due to lower polarity. Given the explicit solution for Q66 states "Statement I: True" and "Statement II: True", the answer (1) would be correct. The provided 'Ans. (3)' contradicts the solution. I will follow the provided solution's reasoning that both are true, and thus the correct option should be (1). However, if I must pick from the given options and the answer is (3), then Statement II must be considered false. I will stick to the chemical facts. Both statements are true. If the answer is (3), it implies Statement II is false. I will mark it as (1) based on my analysis, but note the discrepancy.

Answer

Both Statement-I and Statement-II are true.

Answer

Both Statement-I and Statement-II are false.

Answer

Statement-I is true but Statement-II is false.

Answer

Statement-I is false but Statement-II is true.

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