Which of the following substances is acidic?

How many compounds can be formed when carbon combines with oxygen?

Ions consisting of two or more atoms which have properties similar to halide ions and contain at least one nitrogen atom are called ........

The sides of a matchbox have a coating of:

The silicate anion in the mineral kinoite is a chain of three $SiO_4$ tetrahedra that share corners with adjacent tetrahedra. The mineral also contains $Ca^{2+}$ ions,$Cu^{2+}$ ions,and water molecules in a $1 : 1 : 1$ ratio. The mineral is represented as:

In which of the following silicates,only two corners per tetrahedron are shared?
$I$. Pyro silicate
$II$. Cyclic silicate
$III$. Double chain silicate
$IV$. Single chain silicate
$V$. $3D$ silicate
$VI$. Sheet silicate