Chemistry Test - 32

Except NO₂, all other compounds have linear structure similar to CO₂.

Dichloro diphenyl trichloroethane is a chemical compound commonly used as Insecticide.

• Dichloro diphenyl trichloroethane is commonly known as DDT.
• It is also called 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane.
• It was first developed by Othmar Zeidler in 1874.
• The insecticidal action of DDT was discovered by the Swiss chemist Paul Hermann Müller in 1939.
• Dichloro diphenyl trichloroethane became infamous for its environmental impacts.
• It was used to limit the spread of the insect-born diseases malaria and typhus among civilians and troops during the second half of World War II.
• The United States banned the use of DDT in 1972, but some countries still use the chemical.
• DDT can be absorbed by eating, breathing, or touching products contaminated with DDT.
• It is one of 12 pesticides recommended by the WHO for indoor residual spray programs.

The number of free ions produced in this case is 3. Hence, van't Hoff factor (i) = 3.

Ca(NO₃)₂ → Ca⁺² + 2NO₃^-1

Van't Hoff factor (i) = 3

Number of moles of sulphur = 32/32 = 1 mole

One mole of Na₂S₂O₃ will be obtained from 2 moles of sulphur.

Mole of Na₂S₂O₃ obtained from 1 mole of sulphur = ½ = .50 mole

Standard heat of formation (ΔH_f⁰)of methane is represented by

C (graphite) + 2H2(g)→CH4(g)

3d electrons having s = +1/2 can have the following values of magnetic quantum number.

(-2, -1, 0, +1, +2)

Therefore, option (1) is the correct answer.

ΔH (Rhombic) –ΔH (Monoclinic) = – 70960 – (– 71030) = – 70960 + 71030 = + 70 calories

46 g 28 g

It is clear from the above equation that number of moles of ethene formed = Number of moles of ethanol used

Number of moles of ethene formed = 5.6/28 = 0.2

M = n/V

V = n/M = 0.2/0.1 = 2 L