Ncert Solutions Chemistry Class 11th

Oxygen gas (O? ) is not considered a greenhouse gas.

In sodium hydride (NaH), hydrogen has an oxidation state of -1. In this state, it can only act as a reducing agent.

Oxidation state of N
| NO | +2 |
|-|-|
| NO? | +4 |
| N? O | +1 |
| NO? | +5 |
So, order of oxidation state is
NO? > NO? > NO > N? O

Mn? O? is mixed oxide which contains MnO and Mn? O? , so Mn is in +2 and +3 oxidation state respectively. Both Mn? ² & Mn³? has unpaired electrons so Mn? O? will show magnetic property. While all other oxides have no unpaired electrons either on cation or on anion.

Be is used in X ray tube windows.
Mg is used in incendiary bombs & signals.
Compounds of Ca i.e CaCO? is used in extraction of metals like Fe.
Radium (Ra) is used in treatment of cancer in radiotherapy.

3-Hydroxy propanal

If 7.8g of C? H? O (molar mass 56 g/mol ) is formed, calculate the initial weight of 3-hydroxy propanal (molar mass 74 g/mol ).

Weight = (7.8/56) * 74 * (100/64) [Assuming 64% yield, though the number seems out of place].

Ans ≈ 16 g.

AX is a diatomic molecule with a bond order of 2.5.

The compound is NO. The total number of electrons = 15 (7+8).

The Kjeldahl method is not applicable for nitrogen estimation in:

Compounds containing nitrogen in a nitro group.

Compounds containing an Azo group.

Pyridine.

Please consider the following Image

The addition of HBr to H? C−CH? −CH=CH? proceeds via carbocation formation.

Formation of a 1° Carbocation (A): H? C−CH?

Formation of a 2° Carbocation (B): H? C−CH? −C? H−CH?

The 2° carbocation (B) is more stable than the 1° carbocation (A). Therefore, the activation energy (Ea) for the formation of B is lower, and B is formed faster.