The p-Block Elements Test

Result

The p-Block Elements Test - 17

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

One mole of magnesium nitride on the reaction with an excess of water gives :

A
one mole of ammonia

B
one mole of nitric acid

C
two moles of ammonia

D
two moles of nitric acid

Solution

Hint: Nitride on reaction with water gives ammonia
Step 1: Formula of magnesium nitride
The formula for magnesium nitride will be $$Mg_3N_2$$

Step 2: Recation of magnesium nitride with excess of water
$$Mg_3N_2 + 6H_2O \rightarrow 3Mg(OH)_2 + 2NH_3$$

Hence one mole of magnesium nitride on reaction with excess water gives two moles of ammonia.

Final Step: So the correct answer is option $$C$$.
Question 2
1 / -0

The reaction of white phosphorus with aqueous $$NaOH$$ gives phosphine along with another phosphorus containing compound. The reaction type, the oxidation states of phosphorus in phosphine and the other product are respectively:

A
redox reaction; $$-3$$ and$$-5$$

B
redox reaction; $$+3$$ and $$+5$$

C
disproportionation reaction; $$-3$$ and $$+5$$

D
disproportionation reaction; $$-3$$ and $$+3$$

Solution

$$\overset{0}{P_4} + 3NaOH + 3H_2O \rightarrow \overset{-3}{P}H_3 + 3NaH_2\overset{+1}{P}O_2$$

The salt $$NaH_2PO_2$$ undergoes the following changes on heating.

$$4NaH_2\overset{+1}{P}O_2 \rightarrow Na_4\overset{+5}{P_2}O_7 + 2\overset{-3}{P}H_3 + H_2O$$

The reaction is a disproportionation reaction and the oxidation state of phosphorus are -3 (in phosphine) and +5 in the second product.

Option C is correct.
Question 3
1 / -0

The reaction of $$\mathrm{P}_{4}$$ with X leads selectively to $$\mathrm{P}_{4}\mathrm{O}_{6}$$. The X is:

A
Dry $$\mathrm{O}_{2}$$

B
A mixture of $$\mathrm{O}_{2}$$ and $$\mathrm{N}_{2}$$

C
Moist $$\mathrm{O}_{2}$$

D
$$\mathrm{O}_{2}$$ in the presence of aqueous $$\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}$$

Solution

$$P_4+3O_{2}\overset{N_{2}}{\rightarrow}P_{4}O_{6}$$

White phosphorus on reaction with a limited supply of oxygen gives lower oxide, $$P_4O_6$$.

Therefore, air $$(O_2 + N_2)$$ is a good source for the controlled supply of oxygen and the best choice for controlled oxidation of white phosphorus into lower oxide.

Hence, option B is correct.
Question 4
1 / -0

Bleaching powder and bleach solution are produced on a large scale and is used in several house-hold products. The effectiveness of bleach solution is often measured by iodometry. Bleaching powder contains a salt of an oxoacid as one of its components. The anhydride of that oxoacid is:

A
$$Cl_{2}O$$

B
$$Cl_{2}O_{7}$$

C
$$ClO_{2}$$

D
$$Cl_{2}O_{6}$$

E
$$Cl_2O_3$$

Solution

Bleaching powder is $$Ca(OCl)Cl$$.

So, bleaching powder contains a salt of $$HOCl$$.

$$Cl_2O$$ is an anhydride of $$HOCl$$.

$$Cl_2O+H_2O\Rightarrow 2HOCl$$.

Hence, option A is correct.
Question 5
1 / -0

Concentrated nitric acid, upon long standing, turns yellow-brown due to the formation of :

A
$$NO$$

B
$$NO_{2}$$

C
$$N_{2}O$$

D
$$N_{2}O_{4}$$

Solution

The decomposition of $$HNO_3$$ is represented by the equation:

$$4HNO_{3}\rightarrow 2H_{2}O+4NO_{2}+O_{2}$$

Due to the formation of nitrogen dioxide, it turns yellow-brown.

Hence, option B is correct.
Question 6
1 / -0

The correct structure of tribromooctaoxide is:

A

B

C

D

Solution

The correct structure is A
$$O=\overset{O}{\overset{||}{\underset{O}{\underset{||}{Br}}}}-\overset{O}{\overset{||}{\underset{O}{\underset{||}{Br}}}}-\overset{O}{\overset{||}{\underset{O}{\underset{||}{Br}}}}=O$$
Tribromooctaoxide
Question 7
1 / -0

Which one of the following order is correct for the bond dissociation enthalpy of halogen molecules?

A
$$I_{2} > Br_{2} > Cl_{2} > F_{2}$$

B
$$Cl_{2} > Br_{2} > F_{2} > I_{2}$$

C
$$Br_{2} > I_{2} > F_{2} > Cl_{2}$$

D
$$F_{2} > Cl_{2} > Br_{2} > I_{2}$$

Solution

Bond dissociation energy of halogen family decreases down the group as the size of atom increases.

The decreasing order for the bond dissociation enthalpy of halogen molecules is $$\displaystyle Cl_{2} \text { 57 kcal/mol} > Br_{2} \text { 45.5 kcal/mol} > F_{2} \text { 38 kcal/mol} > \text { 35.6 kcal/mol} I_{2}$$.

A halogen molecule having larger atoms should have low dissociation energy and vice versa. Fluorine is an exception because of interelectronic repulsion is present in small atom fluorine.

Hence, the correct option is $$B$$.
Question 8
1 / -0

For electron affinity of halogens which of the following is correct?

A
$$Br > F$$

B
$$F > Cl$$

C
$$Br < Cl$$

D
$$F < I$$

Solution

Electron affinity decreases in a group from top to bottom due to increase in size, so the expected order of electron affinity for halogens is $$F > Cl > Br > I$$
However, it is not so. The electron affinity of elements of $$III$$ period is higher than that of $$II$$ period because elements of $$II$$ period have a small size and greater electron density so the incoming electrons suffer a repulsive force. Thus the order of electron affinity is $$Cl > F > Br > I$$.
Question 9
1 / -0

Assertion: F is more electronegative than $$Cl$$.
Reason: F has high electron affinity than $$Cl$$.

A
If both assertion and reason are true and the reason is a correct explanation of the assertion

B
If both assertion and reason are true but reason is not a correct explanation of the assertion

C
If the assertion is true but reason is false

D
If both the assertion and reason are false

E
If the assertion is false but the reason is true

Solution

Here assertion is true but reason is false. F is more electronegative than chlorine, in fact it is most electronegative element of the periodic table but its electron affinity, the tendency to accommodate electrons, is less than the $$Cl$$ due to non availability of $$d$$-electrons.
Question 10
1 / -0

Assertion: The fluorine has lower reactivity.
Reason : $$F - F$$ bond has low bond dissociation energy.

A
Both assertion and reason are true and the reason is a correct explanation of the assertion

B
Both assertion and reason are true but reason is not a correct explanation of the assertion

C
Assertion is true but reason is false

D
Both the assertion and reason are false

E
Assertion is false but the reason is true

Solution

Fluorine have the highest electronegativity of all the elements because it has the largest nuclear charge and the least atomic shell, so it has the largest nuclear pull force. In other words, fluoride has the strongest ability to pull or catch an electron to form negative ion (that is, electronegativity).

Bond dissociation energy of $$F_2$$ is fairly low due to the lone pair - lone pair repulsions of the two flourine atoms, which are placed so close to each other due to small size of the atom.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

The p-Block Elements Test - 17

Result

The p-Block Elements Test - 17

Score

-

Rank

-

SHARING IS CARING

Question 1

one mole of ammonia

one mole of nitric acid

two moles of ammonia

two moles of nitric acid

Solution

Question 2

redox reaction; $$-3$$ and$$-5$$

redox reaction; $$+3$$ and $$+5$$

disproportionation reaction; $$-3$$ and $$+5$$

disproportionation reaction; $$-3$$ and $$+3$$

Solution

Question 3

Dry $$\mathrm{O}_{2}$$

A mixture of $$\mathrm{O}_{2}$$ and $$\mathrm{N}_{2}$$

Moist $$\mathrm{O}_{2}$$

$$\mathrm{O}_{2}$$ in the presence of aqueous $$\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}$$

Solution

Question 4

$$Cl_{2}O$$

$$Cl_{2}O_{7}$$

$$ClO_{2}$$

$$Cl_{2}O_{6}$$

$$Cl_2O_3$$

Solution

Question 5

$$NO$$

$$NO_{2}$$

$$N_{2}O$$

$$N_{2}O_{4}$$

Solution

Question 6

Solution

Question 7

$$I_{2} > Br_{2} > Cl_{2} > F_{2}$$

$$Cl_{2} > Br_{2} > F_{2} > I_{2}$$

$$Br_{2} > I_{2} > F_{2} > Cl_{2}$$

$$F_{2} > Cl_{2} > Br_{2} > I_{2}$$

Solution

Question 8

$$Br > F$$

$$F > Cl$$

$$Br < Cl$$

$$F < I$$

Solution

Question 9

If both assertion and reason are true and the reason is a correct explanation of the assertion

If both assertion and reason are true but reason is not a correct explanation of the assertion

If the assertion is true but reason is false

If both the assertion and reason are false

If the assertion is false but the reason is true

Solution

Question 10

Both assertion and reason are true and the reason is a correct explanation of the assertion

Both assertion and reason are true but reason is not a correct explanation of the assertion

Assertion is true but reason is false

Both the assertion and reason are false

Assertion is false but the reason is true

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.