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प्रश्न
Explain by writing a word equation.
Limestone powder disappears on adding to dilute hydrochloric acids.
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उत्तर
Limestone is predominantly Calcium carbonate(CaCO3). When calcium carbonate reacts with a 10% solution of HCl. Then Calcium chloride is formed as a salt along with water and carbon dioxide gas (brisk effervescence).
2HCl + CaCO3 → CaCl2 + CO2 +H2O
In this reaction, we add hydrogen ions (H+), which will react with the carbonate ion [\ce{(CO^{2-}_3)}\] to form hydrogen carbonate \[\ce{(HCO^-_3)}\] ions, which are soluble in water and the limestone will dissolve.
संबंधित प्रश्न
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Miscible liquids having slightly different boiling points can be separated by the
- evaporation
- distillation
- fractional distillation
- sedimentation
MATCH THE COLUMNS
| 1 . `H_2` + `CI_2` `→` 2HCI | a. displacement reaction |
| 2. `2FeCI_3`+ `H_2` `→` `2FeCI_2` +2HCI` | b. addition of an electronegative redical |
| 3. Fe + `CuSO_4` `→``FeSO_4` +Cu` | c. removal of an electronegative redical |
| 4. `2H_2O` +`4NO_2`+`O_2` `→` `4HNO_3` | d.reduction by adding hydrogen |
| 5. 3Fe +`3CI_2` `→` `2FeCI_3` | e.electrolysis of water |
| 6. `FeCI_3`+ 3NaOH `→``Fe(OH)_3``↓`+NaCI | F.double decomposition,precipitation reaction |
| 7.`2H_2O` `→` `2H_2``↑`+`O_2` | e. combination or synthesis reaction |
Fill in the blank:
The substances formed as a result of a chemical reaction are called _______
Write true or false :
When potassium iodide solution is added to lead acetate solution a red precipitate is formed.
Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.
(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)
The white particles of baking soda disappear when put in lemon juice. This means that it is a ______ change.
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.
Give balanced equation for the following conversion affected by heat alone on the substance:
Ammonium dichromate to nitrogen
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.
If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
Can you change rust back into iron by some simple method?
How would you show that the settling of curd is a chemical change?
