Which of the following pairs can be distinguished by the action of heat?

Options

A. `Na_(2)CO_(3) and CaCO_(3)`
B. `K_(2)CO_(3) and MgCO_(3)`
C. `Ca(NO_(3))_(2) and NaNO_(3)`
D. `MgCl_(2).6H_(2)O and CaCl_(2).6H_(2)O`

Answer

A, B

Explanation

`Na_(2)CO_(3)overset(Delta)(rarr)`No reaction
`CaCO_(3)overset(Delta)(rarr)CaO+CO_(2)`
`K_(2)CO_(3)overset(Delta)(rarr)`No reaction
`MgCO_(3)overset(Delta)rarr MgO+CO_(2)`
`Ca(NO_(3))_(2)overset(Delta)(rarr)CaO+2NO_(2)+2NO_(2)+(1)/(2)O_(2)`
`NaNO_(3)overset(Delta)(rarr)NaNO_(2)+(1)/(2)O_(2)`
`MgCl_(2).6H_(2)H_(2)O overset(Delta)(rarr)Mg(OH)Cl+HCl+5H_(2)O`
`CaCl_(2).6H_(2)O overset(Delta)(rarr)CaCl_(2)+6H_(2)O`.