Advertisements
Advertisements
Question
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 – lead [IV] oxide.
Advertisements
Solution
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:
Lead [IV] oxide 2PbO2→2PbO + O2 [g]
Colour change:
Lead [IV] oxide [PbO] – Brown – to Lead monoxide [PbO] – Yellow.
APPEARS IN
RELATED QUESTIONS
Give one example of a chemical reaction characterised by the formation of a precipitate.
Write word equation for the following skeletal equation:
\[\ce{CO + O2 -> CO2}\]
What information do you get from the equation H2+ Cl2 → 2HCl ?
Balance the following equation:
Ca + N2 → Ca3N2
Balance the following equation:
PbS + O2 → PbO + SO2
Give one example in the case where supplying energy [given below] is necessary for a chemical reaction.
Light energy
Name the following:
The gas evolved when a dilute acid is added to chalk [limestone].
Give reason for the following:
Silver salts are kept in dark coloured bottles.
Write word equation for the following chemical reaction given below. Also state the observation seen in the case.
Pb(NO3)2 + 2NH4OH → 2NH4N03 + Pb(OH)2↓
Which of the following is the correct observation of the reaction shown in the above set up?
