When a mixture of white solids Z, is treated with an excess of dilute hydrochloric acid, a colourless gas is evolved and some, (but not all) of the mixture dissolves:
Correct answer: B. BaSO4 and CaCO3
- A. Ba(NO3)2 and Ca(OH)2
- B. BaSO4 and CaCO3
- C. CaCO3 and MgSO4
- D. Ca(OH)2 and MgCO3
Explanation
The correct answer is B, which includes BaSO4 (barium sulfate) and CaCO3 (calcium carbonate).When a mixture of white solids Z is treated with an excess of dilute hydrochloric acid, the reactions can be analyzed:1. BaSO4 (barium sulfate) does not dissolve in dilute hydrochloric acid. The reaction is:BaSO4(s) + 2HCl(aq) → BaCl2(aq) + H2SO4(aq)Since BaSO4 does not dissolve, it does not produce a colorless gas.2. CaCO3 (calcium carbonate) reacts with hydrochloric acid to produce carbon dioxide gas, calcium chloride, and water:CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l)The production of CO2 results in the evolution of a colorless gas.
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About s-Block and p-Block Elements
The s and p blocks are studied through their valence-shell configurations, periodic trends and characteristic chemical properties. Work covers the reactions of Group I and Group II elements, the behaviour of Group IV elements, and how atomic size, ionization energy, electronegativity and metallic character change across periods and down groups.
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