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Question
Identify the gas evolved and give the chemical test in the following case:
Dilute hydrochloric acid reacts with iron (II) sulphide.
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Solution
Gas Evolved: When dilute hydrochloric acid reacts with iron (II) sulphide, the gas evolved is hydrogen sulphide.
Reaction:
\[\ce{FeS + 2HCl -> FeCl2 + H2S ^}\]
Chemical Test for Hydrogen Sulphide: To test for H2S gas, you can use lead acetate paper:
- Moisten a strip of lead acetate paper.
- Expose it to the gas that evolved.
Observation: If H2S is present, the lead acetate paper will turn black due to the formation of lead sulphide (PbS).
\[\ce{Pb(C2H3O2)2 + H2S -> PbS + 2CH3COOH}\]
RELATED QUESTIONS
State one relevant observation for given reactions:
Action of concentrated Sulphuric acid on hydrated copper sulfate
Give one equation to show the following properties of sulphuric acid:
Acidic nature
Why is water not added to concentrated H2SO4 in order to dilute it?
Give two balanced reactions of each type to show the following properties of sulphuric acid:
Hygroscopic nature
Give reason for the following:
When solution of sulphur dioxide is exposed to air, it gets converted to sulphuric acid.
Give reason for the following:
Sulphuric acid can form two kinds of salts with sodium chloride.
Copy and complete the following table.
Column 3 has the names of gases to be prepared using the substance you enter in column 1, along with dilute or concentrated sulphuric acid, as indicated in column 2.
| Column 1 | Column 2 | Column 3 |
| Substance reacted with acid | Dilute or concentrated sulphuric acid | Gas |
| Hydrogen | ||
| Carbon dioxide | ||
| Only chlorine |
Write the equation for the laboratory preparation of :
(i) Sodium sulphate using dilute sulphuric acid.
(ii) Lead sulphate using dilute sulphuric acid.
Write the equation of the following reaction:
Sulphur is heated with concentrated sulphuric acid.
State your observation for the following case :
Moist blue litmus is introduced into a gas jar of sulphur dioxide.
Give two balanced reactions of the type to show the following property of sulphuric acid:
Dehydrating nature
