Chemistry
(i) Give 2 tests to distinguish between HCl solution and Ammonia solution.
(ii) Distinguish between MnO2 and CuO
Analytical Chemistry
3 Likes
Answer
(i) Two tests to distinguish between HCl solution and Ammonia solution:
- HCl turns moist blue litmus paper red, whereas, ammonia gas turns moist red litmus blue.
- With HCl phenolphthalein solution remains colourless whereas, ammonia gas turns it pink.
(ii) Distinguish between MnO2 and CuO:
(a) When each of the compound is heated with conc. hydrochloric acid, greenish yellow (chlorine) gas is evolved in case of manganese dioxide and filtrate is brownish in colour whereas, no chlorine gas is evolved in case of copper oxide and filtrate is bluish in colour.
MnO2 + 4HCl ⟶ MnCl2 + 2H2O + Cl2
CuO + 2HCl ⟶ CuCl2 + H2O
(b) On adding ammonium hydroxide to the above filtrate, no ppt. is formed in case of MnO2, whereas, in case of copper oxide, pale blue ppt. is formed. The ppt. dissolves in excess of ammonium hydroxide forming azure blue colour.
Answered By
1 Like
Related Questions
(i) Define pH. If the hydrogen ion concentration of a solution is 10-12 moles per litre, calculate its pH value.
(ii) What fluid is injected when yellow wasps or white ants bite? How can the pain be relieved?
(iii) A solution of Iron (III) chloride has a pH less than 7. Is the solution acidic or alkaline. Write the equation of its hydrolysis.
(iv) If iron is reacted with dilute sulphuric acid, what will be the product formed ?
What do you observe when —
(i) Ammonia is passed over heated copper oxide.
(ii) Conc. H2SO4 is added to blue vitriol.
(iii) Acetylene is passed into bromine water.
(iv) NaCl is added to silver nitrate solution.
(v) Conc. HCl acid is exposed to atmosphere.
Write an ionic reaction at the electrodes during electroplating of silver over brass spoon after giving the ionisation of the electrolyte.
Draw an electron dot diagram of :
(i) a non-polar hydrocarbon molecule.
(ii) a polar covalent molecule.