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प्रश्न
Fill in the blanK
A .............is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
उत्तर
A catalyst is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
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संबंधित प्रश्न
Name three biochemical catalysts found in the human body.
Complete and balance the following chemical equations
NaCI + `AgNO_3` `→`
Complete and balance the following chemical equations:
Fe `"SO"_4` + NaOH `→`
(aq.) (aq.)
Fill in the blank
A catalyst either ................or ............... the rate of a chemical change but itself remains ............... at the end of the reaction.
Define precipitation.
FILL IN THE BLANK
Negatively charged ions are called ..........
TRUE \ FALSE
A precipitation reaction takes place only in a solution.
TRUE \ FALSE
Copper can displace iron from iron sulphate.
Name three reducing agents ?
Explain the following reaction with one suitable example of Double decomposition 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.
Define the following terms
Precipitate
Define Electrochemical reaction
Give an example
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.
Define:
Photochemical reaction
Give one example
Complete and balance the following reaction:
Pb(NO3)2 + KI →
Complete the following table and write your observations.
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Hydrogen sulphide |
Ammonia |
Sulphur dioxide |
Hydrogen chloride |
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Shake the gas with red litmus solution |
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Shake the gas with blue litmus solution |
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Apply a burning splint to a gas |
Represent the addition of dilute sulphuric acid to zinc by means of a chemical equation. State the function of the arrow between the reactants and products.
Give examples of exothermic reactions i.e. heat evolved in each of the following:
(a) reaction between a solid and a liquid
(b) reaction between two gases
Give two examples of exothermic reactions seen in everyday life.
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.
Give balanced equation for the following conversion affected by heat alone on the substance:
Hydrated copper sulphate to sulphur dioxide
Give balanced equation for the following conversion affected by heat alone on the substance:
Zinc nitrate to nitrogen dioxide
State the following reaction represent oxidation or reduction.
\[\ce{Ag->Ag+}\]
Select the correct answer from the options given below:
State the gaseous product formed, when
An active metal reacts with dilute sulphuric acid.
Discuss how acid rain occurs due to emission of smoke from vehicles and industries?
______ occurs in the absence of air and in the presence of micro-organisms such as yeast.
The chemical name of baking soda is sodium bicarbonate.
The reaction of H2 gas with oxygen gas to form water is an example of ______.
Acid rain is a result of ______.
