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प्रश्न
Define chemical reaction.
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उत्तर
Any chemical change in matter that involves its transformation into one or more new substances is called a chemical reaction.
संबंधित प्रश्न
When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain.
Write the missing reactants and products and balance the equations.
NaOH + ............... `→` NaCI + ...................
Write true or false :
When potassium iodide solution is added to lead acetate solution a red precipitate is formed.
Out of sodium and sulphur which is a metal? Explain its reaction with the oxygen.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Hydrogen chloride
State the original colour of the following substance and colour of residue obtained after heating.
Copper carbonate
Select the correct answer for the following options:
The black residue obtained on heating copper carbonate.
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.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Lead nitrate.
The chemical change is ______.
When an aqueous solution of potassium chloride is added to an aqueous solution of silver nitrate, a white precipitate is formed. Give the chemical equation of this reaction.
Anaerobic bacteria digest animal waste and produce biogas (Change – A). The biogas is then burnt as fuel (Change – B). The following statements pertain to these changes. Choose the correct one.
Chemical change is a temporary change.
The water we drink is a combination of hydrogen and oxygen.
Classify each of the following, as a physical or a chemical change. Give reasons.
(a) Drying of a shirt in the sun.
(b) Rising of hot air over a radiator.
(c) Burning of kerosene in a lantern.
(d) Change the colour of black tea by adding lemon juice to it.
(e) Churning of milk cream to get butter.
Give an example of a chemical reaction for the following situation:
A change in colour is observed
______ occurs in the absence of air and in the presence of micro-organisms such as yeast.
Iron and rust are the same substances.
The chemical name of baking soda is sodium bicarbonate.
Write the effects of chemical reactions.
