The coordination number in a simple cubic $(scp)$ lattice is .......

Which of the following statements is incorrect?

$A$ cubic solid is made of two elements $P$ and $Q$. Atoms of $Q$ are at the corners of the cube and $P$ at the body-centre. What is the formula of the compound? What are the coordination numbers of $P$ and $Q$?

The number of unit cells in $58.5 \ g$ of $NaCl$ is nearly

How many total constituent particles are present in a simple cubic unit cell?

What is the coordination number of a particle in $hcp$ structure?