Which one of the following does not correctly represent the order of the property indicated against it?

If $P=(0,1,0)$ and $Q=(0,0,1)$, then the length of the projection of the line segment $PQ$ on the plane $x+y+z=3$ is

The correct order of acidic strength of the major products formed in the given reactions is:
$A.$ $PhNH_2$ $\xrightarrow[\substack{\text{(2) } CuCN \\ \text{(3) } H_3O^{+} / \Delta}]{\text{(1) } NaNO_2 + HCl \left( < 5^{\circ} C \right)} [A]$
$B.$ $CH_3CH_2CHO \xrightarrow[\Delta]{\left[ Ag \left( NH_3\right)_2\right]^{+}, OH^{-}} [B]$
$C.$ $CH_4 + O_2 \xrightarrow[\text{(ii) } Na_2Cr_2O_7 / H^{+}]{\text{(i) } Mo_2O_3} [C]$
$D.$ $PhCH_2MgBr + CO_2 \xrightarrow[H_3O^{+}]{\text{Dry ether}} [D]$
Choose the correct answer from the options given below:

The value of $a$ for which the equations $x^3+ax+1=0$ and $x^4+ax^2+1=0$ have a common root is

Identify the incorrect statements from the following.
$I$. Tin in $+2$ state acts as reducing agent while lead in $+4$ state acts as strong oxidising agent.
$II$. Silicon exists as $[SiF_6]^{2-}$ form,but $[SiCl_6]^{2-}$ does not.
$III$. The hybridisation of carbon in fullerene is $sp^3$.
$IV$. Among $Ge, Sn$ and $Pb$,the lowest melting point is for $Sn$.

Which one of the following pairs is correctly matched with regard to the codon and the amino acid coded by it?