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प्रश्न
Complete the table given below.
| Heat on Zinc nitrate | Colour of residue |
उत्तर
| Heat on Zinc nitrate | Colour of residue | yellow - hot, white - cold (ZnO Residue zinc oxide) |
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संबंधित प्रश्न
Define; catalyst.
What are (i) positive catalysts and (ii) negative catalysts? Support your answer with one example for each of them.
FILL IN THE BLANK
In a ............ change, new substances are formed.
Write a short note on the information derived from a balanced chemical equation.
Define chemical reaction.
Explain the following reaction with one suitable example of Double decomposition reaction.
Give an example of a reaction where the following are involved
Catalyst
What is a chemical reaction?
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 acid to an active metal.
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A coloured substance which leaves on strong heating a black residue and evolves two colourless gases one of which is acidic and the other neutral.
Complete the table given below.
| Addition of dil. H2SO4 to zinc | Test for gas evolved |
Complete the statement by filling in the blank with the correct word:
The reddish-brown precipitate obtained during a double decomposition precipitation reaction between an iron salt and alkali is __________.
Select the correct answer from the options given below:
State the gaseous product formed, when
An active metal reacts with dilute sulphuric acid.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Ammonium dichromate.
Circle the odd one out. Give reason for your choice
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 the taste.
- The change cannot be reversed.
Choose the correct option from below:
Both CO2 and H2 gases are ______.
______ is a chemical substance is used in whitewashing.
What is thermochemical reactions?
Write the effects of chemical reactions.
