The set in which compounds have different nature is:

$AlF_3$ is soluble in $HF$ only in the presence of $KF$ due to the formation of:

Which of the following halides of group $13$ elements is the most acidic?

Observe the following reactions (not balanced):
$BF_3 + LiAlH_4 \xrightarrow{(C_2H_5)_2O} X + LiF + AlF_3$
$X + NaH \longrightarrow Y$
The incorrect statement about $Y$ is:

Consider the following statements about group $13$ elements:
$A$. $AlCl_3$ achieves stability by forming a dimer.
$B$. $BCl_3$ is an electron-deficient molecule.
$C$. $E^0_{M^{3+}/M^0} \ (V)$ is $+1.26 \ V$ for aluminium.
$D$. In $+1$ oxidation state, thallium is unstable.
The incorrect statements are:

What does orthoboric acid contain?