Question

using a suitable chemical equation justify that some chemical reactions are determined by:-(!)Change in colour (!!) evolution of gas

Answer 1

i hope you will understand my handwriting

Answer 2

1) change in colour-
1. Rust is brown in colour whereas iron is greyish in colour.
2. Lead nitrate and potassium iodine solutions are colourless but on mixing the Two, the precipitate of lead iodine formed is yellow in colour.
3. Red petals of rose when dropped in a jar containing sulphur dioxide gas, red colour decolourize.
4. Potassium dichromate is orange in colour when reacts with sulphur dioxide gas, green coloured chromium sulphate is formed.

2) evolution of gas-
1. When zinc reacts with sulphuric acid zinc sulphate and hydrogen gas is evolved

Hope it helps you
Plzz mark it as brainiest