What is always true of a binary compound? a-it has two elements b-it has two atoms c-it has a double bond d-it has covalent bonds.

Option A, It has two elements

Explanation:

The word binary indicates that a substance consists of two elements. Thus any binary compounds must consists of two different elements. A binary compound may consists of single , double or triple bond. These compounds may be ionic or covalent compound .

Some common examples of binary compound are –  

a)NaCl

b)N2O

c)MgO

d)KI

Hence,  under any circumstance a binary compound consists of two different element.

idk what the options are but

these is a strong electrostatic attraction between the ions hence a lot of energy is needed to overcome this attraction

this is why the boiling points are so high