Question

Give the correct order of initials T or F for following statements. Use T if the statement is true and F if it is false.
S1: $HF$ boils at a higher temperature than $HCl$.
S2: $HBr$ boils at lower temperature than $HI$.
S3: Bond length of $N_2$ is less than $N_2^{+}$.
S4: $F_2$ has higher boiling point than $C{l}_2$.

• A. T F T T
• B. T T F F
• C. T T T F
• D. T T T T

Answer 1

The correct option is C T T T F

S1:
The strength of hydrogen bonding is more in $HF$ than $HCl$ because of the higher polarity of hydrogen in $HF$. Boiling point increase as intermolecular force increases so $HF$ boils at a higher temperature than $HCl$.
S2:
Van der waals force is directly proportional to molecular mass of substance. So Van der waals force in $HBr$ is less than $HI$. Hence, $HBr$ boils at lower temperature than $HI$ as boiling point is directly proportional to the Van der waals force.
S3:
$Bondorder\alpha \frac{1}{Bondlength}$
Bond order of $N_2=3$
Bond order of $N_2^{+}=2.5$
Hence, Bond length of $N_2$ is less than $N_2^{+}$.
S4:
Van der waals force is directly proportional to molecular mass of substance. So, Van der waals force in $F_2$ is less than $C{l}_2$. Hence, $F_2$ boils at lower temperature than $C{l}_2$ as boiling point is directly proportional to the van der waals forces.