Chemistry Test 32

Result

Chemistry Test 32

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Weekly Quiz Competition

Question 1
4 / -1

The substance used in smoke screen is

A
zinc chloride

B
zinc phosphate

C
calcium phosphide

D
calcium fluoride

Solution

The spontaneous combustion of phosphine is technically used in Holme's signals. Containers containing calcium carbide and calcium phosphide are pierced and thrown in the sea when

the gases evolved burn and serve as a signal. It is also used in smoke screens.

Ca₃P₂+ 6H₂O ⟶ 3Ca(OH)₂+ 2PH₃

Phosphene (PH₃) so formed spontaneously catches fire to give P₂O₅.

2PH₃+ 4O₂⟶ P₂O₅+ 3H₂O

P₂O₅ forms a white dense smoke screen.
Question 2
4 / -1

Biotin is an organic compound present in yeast. Its deficiency in diet causes dermatitis and paralysis. It is also known as

A
vitamin H

B
vitamin B₃

C
vitamin B₁₂

D
vitamin D

Solution

Biotin, also known as vitamin H or co-enzyme R, is a water-soluble B-complex vitamin (vitamin B₇).