When kindled, water ..... burn in oxygen, but hydrogen ....... (does/does not)

Classify the following as chemical or physical changes : ** cutting of trees. ** melting of butter in a pan, ** rusting of almirah, ** boiling of water to form steam, ** passing of electric current, through water and the water breaking down into hydrogen and oxygen gases. ** dissolving common salt in water, ** making a fruit salad with raw fruits, and ** burning of paper and wood.

Why does water show high boling points as compared to hydrogen sulphide? Given reason for answer.

Identify the reaction which does not liberatre hydrogen :

Using a burning candle and a jar of hydrogen- how would you prove experimentally that a. Hydrogen is a combustible gas b. Hydrogen does not support combustion.

Atomic hydrogen combaines with almost all elements but molecular hydrogen does not. Explain.

Hard water does not contain :-

On burning hydrogen in air the colour of flame is

Why does a candle become smaller on burning with time?

In water, the hydrogen-to-oxygen mass ratio is

An ore which does not contain oxygen is