For the reaction $C_{(s)} + CO_{2_{(g)}} \rightleftharpoons 2CO_{(g)}$,the partial pressures of $CO_2$ and $CO$ are $2.0 \ atm$ and $4.0 \ atm$ respectively at equilibrium. The $K_p$ for the reaction is

If $\alpha, \beta, \gamma$ are the roots of the equation $x^3+4x+1=0$,then $(\alpha+\beta)^{-1}+(\beta+\gamma)^{-1}+(\gamma+\alpha)^{-1}$ is equal to

Among the second period elements,the actual ionization enthalpies are in the order $Li < B < Be < C < O < N < F < Ne$. Explain why:
$(i)$ $Be$ has higher $\Delta_{i}H$ than $B$.
$(ii)$ $O$ has lower $\Delta_{i}H$ than $N$ and $F$.

The condition for the function $f(x)=x^3+p x^2+q x+r$ $(x \in R)$ to have no extreme value is

The maximum number of sub-levels,orbitals and electrons in $N$ shell of an atom are respectively

Hydathodes are also called