Final answer:
The Ka for an inorganic acid with a pKa of 4.0 is calculated using the formula Ka = 10^-pKa, which results in a Ka value of 1.0 x 10^-4.
Step-by-step explanation:
When dealing with acids and bases, understanding their strengths is key, and this is often communicated through their dissociation constant (Ka) and the pKa value. The pKa is the negative base-10 logarithm of the Ka value; to find the Ka when given a pKa of 4.0, one needs to perform the reverse operation, which is the antilog. The formula to convert pKa to Ka is given by Ka = 10^-pKa.
In this case, to find the Ka for a pKa of 4.0, we would calculate Ka = 10^-4.0 = 1.0 × 10^-4. Therefore, the acid dissociation constant Ka for this inorganic acid would be 1.0 × 10^-4.