MCQ
$X$ is


- A

- ✓

- C

- D







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$C(s) + {O_2}(g) \to C{O_2}(g),\Delta H = - 394\,kJ$
$2{H_2}(g) + {O_2}(g) \to 2{H_2}O(l),\,\Delta H = 568\,kJ$
$C{H_4}(g) + 2{O_2}(g)\,\, \to \,\,C{O_2}(g) + 2{H_2}O(l)$ $\Delta H = - 892\,kJ$ Heat of formation of $C{H_4}$ is.....$kJ$
Assertion $(A)$ : Boron is unable to form $BF _{6}^{3-}$
Reason $(R)$ : Size of $B$ is very small.
In the light of the above statements, choose the correct answer from the options given below.