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प्रश्न
Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
To prevent rusting, a layer of ______ metal is applied on iron sheets.
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उत्तर
To prevent rusting, a layer of zinc metal is applied on iron sheets.
Reason:
Zinc is a non-corrosive metal. Therefore, a layer of zinc prevents rusting.
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संबंधित प्रश्न
How do the following help in bringing about a chemical change?
light.
How do the following help in bringing about a chemical change?
catalyst .
Fill in the blanK
A .............is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
Classify the following reaction as combination, decomposition, displacement, precipitation and neutralization. Also balance the equation.
\[\ce{NH3_{(g)} + HCl_{(g)} -> NH4Cl_{(s)}}\]
TRUE \ FALSE
Ammonia is a good oxidizing agent.
What is the reaction called when oxidation and reduction take place simultaneously? Explain with one example.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Potassium fluoride
Complete and balance the following reaction:
\[\ce{CuCO3 ->[\Delta]}\]
Give a word equation for the following reaction.
Two solids which combine on heating, to give a liquid.
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.
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 water to quicklime.
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 white solid which evolves two colourless gases which on cooling combine and condense on the cooler parts of the test tube.
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 |
Differentiate between the following:
Neutralization reaction and a precipitation reaction.
The changes in which new substance with new chemical properties are formed are ______.
Chemists identify gypsum as a natural indicator.
The water we drink is a combination of hydrogen and oxygen.
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.
Are these changes chemical in nature?
Magnesium + oxygen → magnesium oxide.
2Mg + O2 → 2Mg O
______ is a chemical substance is used in whitewashing.
