What is a bond between a positive and a negative ion called?

Answer is: ionic bond.

Ionic bond is the electrostatic attraction between oppositely charged ions, cations (positive ions) and anions (negative ions).

For example compound magnesium chloride (MgCl₂) has ionic bond. Magnesium transfers two electrons, form positive cation Mg²⁺, to chlorine, form anion Cl⁻.

Another example, potassium bromide (KBr) is ionic solid, it has ionic bonds.

answer: c.

explanation:

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.