Producer gas is a mixture of

The element similar to carbon is

Which of the following statements are correct?
$(a)$ The isotope of carbon containing $7$ neutrons has natural abundance of $1.1 \%$.
$(b)$ Among the $IV$ $A$ group elements, $Sn$ has the lowest melting point.
$(c)$ Silicon is the $2^{nd}$ (by mass) most abundant element in the earth's crust.
$(d)$ Elemental carbon shows the highest electrical resistivity among the $14$ group elements.

Name the kind of silicate formed when two silicate units $(SiO_4)^{4-}$ share one oxygen atom.

Identify the correct statements:
$I)$ $CO$ reduces the oxygen carrying ability of blood.
$II)$ Producer gas contains $CO$ and $N_2$.
$III)$ $C-O$ bond length in $CO_2$ is $115 \ pm$.

For a good quality cement,the ratio of silica to alumina is found to be