Chemistry Class 11 NCERT Solutions: Chapter 12 Organic Chemistry Some Basic Principles and Techniques Part 15

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Q: 32. An organic compound contains carbon and hydrogen, the remainder being oxygen. Calculate the masses of carbon dioxide and water produced when of this substance is subjected to complete combustion.

Answer:

Percentage of carbon in organic compound

That is, of organic compound contains of carbon.

of organic compound will contain

Molecular mass of carbon dioxide,

That is, of carbon is contained in of

Therefore, of carbon will be contained in

Thus, will be produced on complete combustion of of organic compound.

Percentage of hydrogen in organic compound is

i.e., of organic compound contains of hydrogen.

Therefore, of organic compound will contain

It is known that molecular mass of water is .

Thus, of hydrogen is contained in of water.

of water

Thus, of water will be produced on complete combustion of of the organic compound.

Q: 33. A sample of of an organic compound was treated according to Kjeldahl’s method. The ammonia evolved was absorbed in of 0.5 M . The residual acid required of solution of for neutralisation. Find the percentage composition of nitrogen in the compound.

Answer:

Given that, total mass of organic compound

mL of M solution of was required by residual acid for neutralisation.

mL of M solution

∴Acid consumed in absorption of evolved ammonia is

Again,

Also, since 1000 mL of 1 MNH3 contains 14 g of nitrogen,

will contain

Therefore, percentage of nitrogen in of organic compound

Q: 34. of an organic chloro compound gave of silver chloride in Carius estimation. Calculate the percentage of chlorine present in the compound.

Answer:

Given that

Mass of organic compound is

Mass of formed

1 mol of contains of .

Thus, mass of chlorine in of

∴ Percentage of chlorine

Hence, the percentage of chlorine present in the given organic chloro compound is .

Q: 35. In the estimation of sulphur by Carius method, of an organic sulphur compound afforded of barium sulphate. Find out the percentage of sulphur in the given compound.

Answer:

Total mass of organic compound

Mass of barium sulphate formed

Thus, of contains of sulphur g of sulphur

Therefore, percentage of sulphur

Hence, the percentage of sulphur in the given compound is .

Q: 36. In the organic compound , the pair of hybridised orbitals involved in the formation of: bond is:

(A)

(B)

(C)

(D)

Answer:

In the given organic compound, the carbon atoms numbered as and are , and hybridized respectively. Thus, the pair of hybridized orbitals involved in the formation of bond is sp .