A solid compound 'X' on heating gives CO2 gas and a residue. The residue mixed with water forms 'Y'. On passing an excess of CO2 through 'Y' in water, a clear solution, 'Z' is obtained. On boiling 'Z', compound 'X' is reformed. The compound 'X' is:
Correct answer: D. CaCO3
- A. Na2CO3
- B. K2CO3
- C. Ca(HCO3)2
- D. CaCO3
Explanation
Upon heating, compound 'X' decomposes into CaO and CO2. The residue from this reaction, when mixed with water, forms Ca(OH)2 (Y). Upon passing an excess of CO2 through Ca(OH)2, it forms CaCO3 and H2O, which upon boiling results in the reformation of compound 'X' (CaCO3). The incorrect options fail to match the observed reactions and compounds formed as described in the question.
Last updated
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.
Practise s-Block and p-Block Elements
1,359 free s-Block and p-Block Elements MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Chemistry questions like this
Chemistry is on 12 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
2NaOH(aq) + Cl2(g) → NaCl + NaClO + H2O proceed at:
A compound 'X' on heating gives a colourless gas. The residue is dissolved in water to produce 'Y'. When CO₂ is passed through the aqueous solution of 'Y', it produces 'Z', which on gentle heating gives back 'X'. Compound 'X' is:
A elements are named as alkali metals because
A gas which burn with blue flame is:
A gas which burns with a blue flame is