Question

1g of solid sodium chloride in taken in a clean and dry test tube and 2ml of cone, sulphuric acid is added to it. If the gas evolves is tested first with dry and then with we blue litmus paper. Give reason for your answer. What inference can be drawn about the nature of the evolved gas? Support your answer with chemical equation for the reaction. ​

Answer 1

Chemical Reactions

A chemical reaction can be identified when indicators show a characteristic change. Here Blue Litmus Paper has been used.

Important Details

• Sodium Chloride = NaCl

• Sulphuric Acid = $H_2 SO_4$

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Reaction

$\small{ 2NaCl + H_2 SO_4 \Longrightarrow Na_2 SO_4 + 2HCl }$

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Observations :

• Gas evolved is HCl which turn blue Litmus red.

• Dry blue litmus paper will remain unchanged but he wet blue litmus will remain unchanged.

(Reason : Because acid show there acidic properties only in presence of water)

• The gas remains colourless in room temperature and creates white fumes of HCl when acter by water vapour.