Study of the First Element - Hydrogen — CHEMISTRY STD 9 — Question

Identify the gases from the observations:
A colourless gas having a suffocating smell. It turns limewater milky and potassium dichromate solution green.

Explain why:
If distilled water is kept in a sealed bottle for a long time, it leaves etchings on the surface of the glass.

Why is cigarette-smoking harmful?

What do you observe? When
Silver chloride is exposed to sunlight.

Give the formula and valency of :
chromate ________ .

Compare hydrogen and halogens on the basis of :
valency

Which metal is preferred for collecting hydrogen from Cold water?Write the balanced equation.

Identify the gases from the observations:
A colourless gas having a rotten eggs like smell. It turns limewater milky and moist lead acetate paper silvery black.

Name and state the following with reference to the elements of the first three periods of the periodic table.
Typical elements of Groups 14 and 15.