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प्रश्न
Explain why dilute hydrochloric acid cannot be concentrated by boiling beyond 22.2%.
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उत्तर
Distillation slowly increases the strength of a weak hydrochloric acid solution until it has 22.2% HCl by weight and boils at 110°C. Once this level is reached, boiling cannot be used to make the acid stronger anymore. When this concentration is attained, boiling [constant boiling mixture or azeotrope] cannot be used to enhance the acid concentration any further.
Water and HCl are the main components of vapours that form before 110°C, although HCl molecules make up the majority of vapours that form above this temperature.
संबंधित प्रश्न
State your observations when Dilute Hydrochloric acid is added to Copper carbonate
The acid on mixing with silver nitrate solution produces a white precipitate which is soluble in excess ammonium hydroxide
Name the gas that is produced in the given cases :
An action of dilute hydrochloride acid on sodium sulphide.
Write an equation for the reaction of hydrochloric acid on magnesium foil.
How will you identify?
An amphoteric hydroxide
Match the following:
| Column A | Column B |
| 1. A substance that turns moist starch iodide paper blue. | A. Ammonium sulphate |
| 2. A compound which release a reddish brown gas on reaction with concentrated sulphuric acid and copper turnings. | B. Lead carbonate |
| 3. A solution of this compound gives dirty green precipitate with sodium hydroxide. | C. Chlorine |
| 4. A compound which on heating with sodium hydroxide produces a gas which forms dense white fumes with hydrogen chloride. | D. Copper nitrate |
| 5. A white solid which gives a yellow residue on heating | E. Ferrous sulphate |
Write the balanced equation for the reaction of dilute hydrochloric acid with the following:
Magnesium sulphite
State your observation when:
Decomposition of bicarbonates by dil. H2SO4
2NaHCO3 + H2SO4 → Na2SO4 + 2H2O + 2CO2
2KHCO3 + H2SO4 → K2SO4 + 2H2O + 2CO2
State which of the two - a solution of HCl in water or in toluene is an electrolyte. Explain.
A solution of hydrogen chloride in water is prepared. The following substances are added to separate portions of the solution :
| S.NO. | Substances added | Gas evolved | Odour |
| 1. | Calcium carbonate | ______ | ______ |
| 2. | Magnesium ribbon | ______ | ______ |
| 3. | Manganese (IV) oxide with heating | ______ | ______ |
| 4. | Sodium sulphide | ______ | ______ |
Complete the table by writing the gas evolved in each case and its odour.
