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प्रश्न
Give two examples where a chemical reaction is accompanied by a change in colour of the reactants and products on completion of the reaction.
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उत्तर
(i) \[\ce{\underset{\text{magnesium}}{Mg} + \underset{\text{Blue copper sulphate}}{CuSO4} ->\underset{\text{colourless magnesium sulphate}}{MgSO4}+\underset{\text{copper}}{Cu}}\]
(ii) \[\ce{2Pb[NO3]2->\underset{\text{litharge (yellow)}}{2PbO} + 4NO2 + O2}\]
(iii) \[\ce{\underset{\text{colourless}}{Pb[NO3]} + 2Kl->\underset{\text{yellow ppt.}}{Pbl2 v} + 2KNO3}\]
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संबंधित प्रश्न
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Which one of the following alters the rate of the chemical reaction without itself undergoing any change?
- temperature and Pressure
- concentration of reactants
- presence of catalyst
- none of these
TRUE \ FALSE
Temperature at which a liquid starts boiling is known as the boiling point of that liquid. True or false ?
Balancing a chemical equation is based on
Give reason for the following:
Colourless concentrated sulphuric acid in a test tube changes to blue on adding a small piece of copper to it.
When hydrogen burns in oxygen, water is formed; when electricity is passed through water, hydrogen and oxygen are given out. Name the type of chemical change involved in the two cases.
Complete and balance the following reaction:
\[\ce{NH3 + O2 ->[\Delta]}\]
Complete the table given below.
| Heat on copper carbonate | Test for gas evolved |
State the following reaction represent oxidation or reduction.
\[\ce{Ag->Ag+}\]
Two chemical species X and Y combine together to form a product P which contains both X and Y
\[\ce{X + Y -> P}\]
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following concerning the species X, Y and P are correct?
(i) P is a compound
(ii) X and Y are compounds
(iii) X and Y are elements
(iv) P has a fixed composition
Which of the following is/are true when milk changes into curd?
- Its state is changed from liquid to semi solid.
- It changes colour.
- It changes taste.
- The change cannot be reversed.
Choose the correct option from below:
