Tag: chemistry

Questions Related to chemistry

Which of the following possesses the highest bond energy?

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. $F _2$

  2. $Cl _2$

  3. $Br _2$

  4. $I _2$

Show answer
Correct Option: B
Explanation:

$F _2$ is a smaller molecule than $Cl _2$. This means that the bonded electrons in $F _2$ are closer to the outer shell unbonded electrons. Due to the electron repulsion theory, the bonded electrons repel the outer shell unbonded electrons far more in $F _2$ than they would in $Cl _2$. 


since  $Cl _2$ has more shells so more shielding of the outer electrons. The fact that the bonded electrons in $F _2$ repel the unbonded electrons so much makes the molecule weak, so it is easier to break. 


Hence option B is correect.

Which of the following is incorrect?

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. Among $Cl, Ar $ and $ K$, $K$ has the smallest ionization potential.

  2. Among $CH _4,\, NH _3,$ and $ HF$,$ HF$ has the highest boiling point.

  3. Among $Cl _2,\, Br _2,\, and\, l _2,\, Br _2$ has the lowest boiling point.

  4. None of the above.

Show answer
Correct Option: C
Explanation:
K is a metal and has 1 valence electron, which can be removed easily to attain nearest noble gas configuration. Hence, it has the lowest Ionization energy. 

Argon is already stable and has 8 electrons in it's outermost shell. Cl needs one more electron as it has 7 valence electrons. It is very difficult to remove an electron form Cl due to high electronegativity.

HF has the highest boiling point compared to methane and ammonia due to the strong hydrogen bonding.

Chlorine is a gas, bromine is a liquid and iodine is a solid at room temperature. As the atomic number increases, atomic size increases and due to the increase in surface area, the boiling point increases. Hence, chlorine has lowest boiling point.

Hence, option C is correct.

Select the correct increasing order of $\pi$ bond formation tendency from the following :

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. $Si\, -\, O\, >\, P\, -\, O\, >\, S\, -\, O\, >\, Cl\, -\, O$

  2. $Si\, -\, O\, <\, P\, -\, O\, <\, S\, -\, O\, <\, Cl\, -\, O$

  3. $Cl\, -\, O\, <\, Si\, -\, O\, <\, P\, -\, O\, <\, S\, -\, O$

  4. $Si\, -\, O\, <\, Cl\, -\, O\, <\, P\, -\, O\, <\, S\, -\, O$

Show answer
Correct Option: B
Explanation:

The correct increasing order of the pi bonding tendency is $Si\, -\, O\, <\, P\, -\, O\, <\, S\, -\, O\, <\, Cl\, -\, O$.
This is because, with decrease in the size from Si to Cl, the effectiveness of the sideways overlap increases.

Match the following
Set- I                              Set - II
A) $F _{2}$               1) pale yellow colour gas
B)$Cl _{2}$               2) violet colour solid
C)$Br _{2}$              3) orange liquid
D)$I _{2}$                 4) greenish colour gas
Correct the matching is

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. A-1, B-3, C-2, D-4

  2. A-1, B-4, C-3, D-2

  3. A-2, B-3, C-4, D-1

  4. A-3, B-2, C-1, D-4

Show answer
Correct Option: B
Explanation:

$F _{2}$ - pale yellow colour gas

$Cl _{2}$ - greenish colour gas

$Br _{2}$ - orange liquid

$I _{2}$ - Violet colour solid

A) 1

B) 4

C) 3

D) 2

The colour of iodine is:

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. violet

  2. green

  3. white

  4. brown

Show answer
Correct Option: A
Explanation:

Iodine has atomic number 53 belonging to group 17. The name is from Greek meaning violet or purple due to the colour of elemental iodine vapour. It is a bluish-black solid with a metallic lustre sublimating into violet-pink gas and colour is due to absorption of visible light by an electronic transition between highest and lowest molecular orbitals.

The only liquid non-metal is:

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. $Br$

  2. $Fl$

  3. $Cl$

  4. $As$

Show answer
Correct Option: A
Explanation:

Bromine is a liquid non-metal because the inter-molecular forces in bromine are very strong and hence it does not vaporise to gaseous form and remains in liquid state itself.

Which of the following is not the characteristic of interhalogen compounds?

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. They are covalent

  2. More reactive than halogens

  3. Have low B.P. and high volatile

  4. Quite unstable but not explosive

Show answer
Correct Option: C
Explanation:

Interhalogen compounds are covalent in nature. More reactive than halogens because of low bond energy due to dissimilar size of atoms in molecule. As the molecule becomes a little polar the boiling point increases due to inter-molecular attraction. They are reactive and unstable because of low bond energy. 

Which of the following non-metal appears as a liquid under standard condition?

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. $\displaystyle F$

  2. $\displaystyle Cl$

  3. $\displaystyle Br$

  4. $\displaystyle I$

  5. $\displaystyle At$

Show answer
Correct Option: C
Explanation:

Bromine is the only non metal to exists in liquid state.

It is brown in colour.

Which of the following contain elements in the solid, liquid and gas phases at STP?

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. Halogens

  2. Alkali metals

  3. Alkaline earth metals

  4. Noble gases

  5. Lanthanides

Show answer
Correct Option: A
Explanation:

Fluorine and chlorine are gases, bromine is a liquid and iodine is solid at STP conditions.

$I$. Under standard conditions the states of the elemental forms of the halogens are: iodine-solid, bromine-liquid, chlorine-gas, fluorine-gas.
$II$. Diatomic halogen molecules exhibit dispersion forces and increase in mass moving down through the family.

chemistry group 17 group 17 - physical properties physical properties of group 17 elements group 17 elements: the halogen family

  1. Statement $I$ is true, Statement $II$ is true and is a correct explanation of the phenomena described in $I$

  2. Statement $I$ is true, Statement $II$ is false

  3. Statement $I$ is false, Statement $II$ is true

  4. Statement $I$ is false, Statement $II$ is false

Show answer
Correct Option: A
Explanation:

Here, Iodine, bromine, chlorine and fluorine belongs to the same group. The order of their atomic mass are: 

$I > Br > Cl > F$
These diatomic atoms are having dispersion forces between them. So, their state completely depend upon their atomic mass. 
So, correct answer is option $A$.