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प्रश्न
A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Thermal decomposition of mercury [II] oxide.
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उत्तर
Thermal decomposition of mercury [II] oxides: Red colour of Hg[II]0 changes to silvery (Hg metal).
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संबंधित प्रश्न
Give reason.
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MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
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A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Addition of dilute hydrochloric acid to silver nitrate.
Give balanced equation for the following conversion affected by heat alone on the substance:
Copper nitrate to nitrogen dioxide
Give balanced equation for the following conversion affected by heat alone on the substance:
Ammonium dichromate to nitrogen
State the following reaction represent oxidation or reduction.
\[\ce{Cl- ->Cl}\]
State the following reaction represent oxidation or reduction.
\[\ce{Cu++->Cu}\]
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When lithium metal is placed in hydrochloric acid, _______ gas is evolved.
______ is a natural indicator.
Give an example of a chemical reaction for the following situation:
A change in colour is observed
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What changes do you expect?
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