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प्रश्न
Fill in the blank.
The formation of gas bubbles in a liquid during a reaction is called ......................
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उत्तर
The formation of gas bubbles in a liquid during a reaction is called effervesence
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संबंधित प्रश्न
Fill in the blank
A catalyst either ................or ............... the rate of a chemical change but itself remains ............... at the end of the reaction.
Give reason.
Acidic soil is treated with quick lime.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Reduction reaction is the exact opposite of
- displacement reaction
- decomposition reaction
- oxidation reaction
- none of these
Define electrolysis.
A chemical equation is a statement that describes a chemical change in terms of
Explain the following reaction with one suitable example of Displacement reaction.
A solution of a substance ‘X’ is used for white washing write the reaction of the substance ‘X’ named in (a) above with water.
Explain by writing a word equation.
Limestone powder disappears on adding to dilute hydrochloric acids.
Give an example of a reaction where the following are involved:
Close contact
Write the chemical reaction where the following changes are observed.
Colour change is noticed
Give reason for the following:
Blue solution of copper sulphate changes to green when a piece of iron is added to this solution.
State the original colour of the following substance and colour of residue obtained after heating.
Copper carbonate
Distinguish by heating the following in dry test tubs.
Zinc nitrate and copper nitrate.
Distinguish by heating the following in dry test tubs.
Copper Sulphate and copper carbonate
Write your observation and a balanced equation in the case of the following substances being heated.
Copper carbonate.
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 – Thermal decomposition of mercury [II] oxide.
On heating which of the following substances i.e. copper carbonate, zinc carbonate, washing soda, copper sulphate, zinc nitrate, copper nitrate, lead nitrate, ammonium chloride and ammonium dichromate – relate to the reaction given below.
A coloured substance which leaves a black residue and evolves two gases one of which is acidic and coloured and the other neutral and colourless.
Select the correct answer from the options given below:
State the gaseous product formed, when
An active metal reacts with dilute sulphuric acid.
Classify the following as physical or chemical properties
Most metal oxides form alkalis on interacting with water.
