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प्रश्न
Write true or false :
When potassium iodide solution is added to lead acetate solution a red precipitate is formed.
विकल्प
True
False
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उत्तर
False
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संबंधित प्रश्न
Changes in which new substances are formed are called ______ changes.
FILL IN THE BLANK
In a double decomposition precipitation reaction both the reactants must be ............ soluble.
Name three reducing agents ?
Fill in the blank
A new substance is formed in a _______ change.
Fill in the blank:
During a chemical reaction transfer of ________ takes place.
Fill in the blank:
The basic conditions necessary for a chemical reaction is _______
Define an electrochemical reaction.
Complete and balance the following reaction:
\[\ce{CuCO3 ->[\Delta]}\]
Distinguish by heating the following in dry test tubs.
Zinc carbonate, Copper carbonate and lead carbonate.
Give balanced equation for the following conversion affected by heat alone on the substance:
Copper nitrate to nitrogen dioxide
Complete the table given below.
| Addition of dil. H2SO4 to FeS | Odour of gas evolved |
Complete the table given below.
| Addition of dil. H2SO4 to KHCO3 | Name of residue obtained |
Match the chemical reactions in List I with the appropriate answer in List II.
| List I | List II | ||
| 1. | \[\ce{XY⇌[heat]X + Y}\] | A: | Displacement reaction |
| 2. | \[\ce{XY->X + Y}\] | B: | Double decomposition |
| 3. | \[\ce{X+Y- + A+B^-->X+B- + A+Y-}\] | C: | Endothermic reaction |
| 4. | \[\ce{X + YZ->XZ + Y}\] | D: | Thermal dissociation |
| 5. | \[\ce{X + Y->[heat]XY -\Delta}\] | E: | Decomposition reaction |
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.
State whether the following statement is true or false:
When a candle burns, both physical and chemical changes take place.
A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.
What changes do you expect?
Iron and rust are the same substances.
Match the following:
| Column I | Column II | ||
| 1. | Burning of coal | a. | Rusting |
| 2. | Painting of a surface | b. | Evaporation |
| 3. | Dipping iron in the water | c. | Chemical change |
| 4. | Salt from seawater | d. | Prevention of rusting |
Assertion (A): Cutting paper into very small pieces is an irreversible change.
Reason (R): Physical changes are always reversible.
What are the chemical reactions that occur in everyday life?
