Among the following solid carbonates, select all that decompose with evolution of CO2 on strong heating in a Bunsen flame (take the alkali metal carbonates Na2CO3 and K2CO3 as stable at this temperature).

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Among the following solid carbonates, select all that decompose with evolution of $CO X_{2}$ on strong heating in a Bunsen flame (take the alkali metal carbonates $Na X_{2} CO X_{3}$ and $K X_{2} CO X_{3}$ as stable at this temperature).

ZnCO X_{3} ZnO + CO X_{2}

and

CuCO X_{3} CuO + CO X_{2}

(black residue). The alkali metal carbonates

Na X_{2} CO X_{3}

and

K X_{2} CO X_{3}

do not decompose at this temperature. So only the zinc and copper carbonates qualify.