Which of the following is an example of a covalent crystal solid?

Which of the following dopant is used in silicon to produce $p$-type semiconductor?

Which of the following components in cement sets at the slowest rate?

Classify each of the following solids as ionic,metallic,molecular,network (covalent) or amorphous.
$(i)$ Tetra phosphorus decoxide $(P_{4}O_{10})$ $(ii)$ Ammonium phosphate $(NH_{4})_{3}PO_{4}$
$(iii)$ $SiC$ $(iv)$ $I_{2}$ $(v)$ $P_{4}$ $(vi)$ Plastic $(vii)$ Graphite $(viii)$ Brass $(ix)$ $Rb$ $(x)$ $LiBr$ $(xi)$ $Si$

Which of the following is not a property of solids?

Given below are two statements.
Statement $I$ : $O_2, Cu^{2+}$ and $Fe^{3+}$ are weakly attracted by magnetic field and are magnetized in the same direction as magnetic field.
Statement $II$ : $NaCl$ and $H_2O$ are weakly magnetized in opposite direction to magnetic field.
In the light of the above statements,choose the most appropriate answer from the options given below: