If the pH value decreases from 7 to 3, what change occurs in the nature of the solution?

Correct answer: The solution becomes more acidic

On the pH scale, 7 represents neutrality, values below 7 indicate acidity, and values above 7 indicate basicity. A fall from pH 7 to pH 3 therefore changes the solution from neutral to acidic. Because pH is logarithmic, pH 3 also represents a much greater hydrogen-ion concentration than pH 7. Hence option A is correct; the other choices reverse or deny the pH relationship.