Each pair forms an ideal solution except:

Which of the following is the correct decreasing order of thermal stability of alkaline earth metal carbonates?

The reading of a spring balance corresponds to $100 N$ while situated at the north pole and a body is kept on it. The weight record on the same scale if it is shifted to the equator, is $...........\,N$

(take, $g =10 m / s ^2$ and radius of the earth, $R =6.4 \times 10^3 m$ )

$Cl_2 + \mathop{NaOH}\limits_{(\text{dil and cold})} \longrightarrow A + B + H_2O$. The anions of $A$ and $B$ are respectively . . . . . . .

$AB_{3(g)}$ dissociates as $AB_{3(g)} \rightleftharpoons AB_{2(g)} + \frac{1}{2}B_{2(g)}$. When the initial pressure of $AB_3$ is $800 \ torr$ and the total pressure at equilibrium is $900 \ torr$,what fraction of $AB_{3(g)}$ is dissociated (in $\%$)?

The oxide of a metal contains $40 \%$ of oxygen. The valency of the metal is $2$. What is the atomic weight of the metal?