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 – copper carbonate.
Advertisements
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:
Copper carbonate CuCO3 → CuO + CO2[g]
Colour change:
Copper carbon [CuCO3] – Green – to Copper [III] oxide [CuO] – Black
APPEARS IN
संबंधित प्रश्न
Balance the following equations:
\[\ce{Al(OH)3 -> Al2O3 + H2O}\]
A metal X forms a salt XSO4. The salt XSO4 forms a clear solution in water which reacts with sodium hydroxide solution to form a blue precipitate Y. Metal X is used in making electric wires and alloys like brass.
- What do you think metal X could be?
- Write the name, formula and colour of salt XSO4.
- What is the blue precipitate Y?
- Write a chemical equation of the reaction which takes place when salt XSO4 reacts with sodium hydroxide solution. Give the state symbols of all the reactants and products which occur in the above equation.
Complete the following equation:
CH3COOH + NaOH →
Balance the following equation:
Fe + H2O → Fe3O4 + H2
Balance the following equation:
PbS + O2 → PbO + SO2
Write the balanced chemical equations of the following reactions.
chlorine + sulphur dioxide + water → sulphuric acid + hydrogen chloride
Write the balanced chemical equation of the following reaction.
sodium chloride + manganese dioxide + sulphuric acid → sodium hydrogen sulphate + manganese sulphate + water + chlorine.
\[\ce{MnO2 + 4HCl -> MnCl2 + 2H2O + Cl2}\]
0.02 moles of pure MnO2 is heated strongly with conc. HCl. Calculate mass of MnO2 used.
Explain the term ‘chemical equation’.
Balance the given chemical reaction as per the instructions below.
\[\ce{NaOH + H2SO4 -> Na2SO4 + H2O}\]
Write names of reactants and products of chemical reaction.
