To keep ionic strength constant and maintained a more consistent matrix in a solution where ions could be influencing each other, another component is often added to the solution. This is an ionic compound, not involved directly with the reaction, called an ionic strength adjuster (ISA) ingredient. This is an important consideration in investigations using selective electrodes. What is the ionic strength (I) of a solution that contains 0.0280 M (NH4)2SO4 as the ISA ingredient?
(NH4)2SO4(s)→ 2 NH4+ (aq) + SO42-(aq)