Advertisements
Advertisements
प्रश्न
A chemical reaction is generally accompanied by certain external indications or characteristics. These include – change of – (a) colour (b) state (c) smell (d) evolution of gas (e) formation of precipitate (f) evolution or absorption of heat. With reference to change of colour – state the change in colour seen when the following are heated – zinc carbonate.
उत्तर
Change of colour — In certain chemical reactions a change of colour is seen to be observed. Heat on substances to observe change in colour of reactants and products.
Heat on:
Zinc carbonate ZnCO3 → ZnO + CO2 [g]
Colour change:
Zinc carbonate [ZnCO3] – White – to Zinc oxide [ZnO] – Yellow (when hot)
APPEARS IN
संबंधित प्रश्न
Giving examples, state the difference between balanced and unbalanced chemical equations.
Balance the following equation and add state symbols:
Zn + HCI → ZnCI2 + H2
Is Electrolysis of water an endothermic reaction or an exothermic reaction?
Write symbolic representation for the following word equation and balance them :
Calcium oxide + Water → Calcium hydroxide
Balance the following equation:
PbO + NH3 → Pb + H2O + N2
Balance the following equation:
MnO2 + HCl → MnCl2 + H2O + Cl2
Grills of doors and windows are always painted before they are used.
Identify the type of reaction taking place of the following case and write the balanced chemical equation of the reaction:
Zinc reacts with silver nitrate to produce zinc nitrate and silver.
Name the following:
The silvery residue obtained on heating mercury [II] oxide.
Which among the following statement(s) is(are) true? ‘Exposure of silver chloride to sunlight for a long duration turns grey due to
- the formation of silver by decomposition of silver chloride
- sublimation of silver chloride
- decomposition of chlorine gas from silver chloride
- oxidation of silver chloride
