Which type of impurity is to be added to a pure semiconductor to get a $p$-type semiconductor?

Explain $n$-type and $p$-type semiconductors based on energy band theory.

To obtain $P$-type $Si$ semiconductor,we need to dope pure $Si$ with

$P$-type semiconductors are made by adding which impurity element?

What will be the conductivity of a pure silicon crystal at $300 \ K$ temperature,if the electron-hole pairs per $cm^3$ is $1.072 \times 10^{10}$ at this temperature,$\mu_e = 1350 \ cm^2/V \cdot s$ and $\mu_h = 480 \ cm^2/V \cdot s$?

$A$ semiconductor has equal electron and hole concentration of $2 \times 10^8 \ m^{-3}$. On doping with a certain impurity, the electron concentration increases to $4 \times 10^{10} \ m^{-3}$. What is the new hole concentration of the semiconductor?