Question

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Answer 1

Answer:

1.heat is evolved as it is exothermic reaction.

2.litmus is obtained from extracts of lichen plant.......

Answer 2

Answer:

1. Reaction of acid with hydrogen carbonates (bicarbonates):

Acids give carbon dioxide gas, respective salt and water when they react with metal hydrogen carbonate. ... The gas evolved because of reaction of acid with metal carbonate or metal hydrogen carbonate turns lime water milky.

2. lichens

Litmus is a water-soluble mixture of different dyes extracted from lichens. It is often adsorbed onto filter paper to produce one of the oldest forms of pH indicator, used to test materials for acidity

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