A sample of grape juice has a hydroxide ion concentration of 1.4 × 10-10 M. Is the grape juice more or less acidic than a sample of orange juice that has a hydronium ion concentration of 1.8 × 10-4 M? To compare the acidity of the orange juice and grape juice, compare the hydronium ion concentrations and/or pH values of the two solutions. How does the acidity of a solution vary with hydronium ion concentration and pH? a. Acidity increases as the hydronium ion concentration increases and the pH increases.b. Acidity increases as the hydronium ion concentration decreases and the pH increases.c. Acidity increases as the hydronium ion concentration increases and the pH decreases. d. Acidity increases as the hydronium ion concentration decreases and the pH decreases.