Answer
(d) 0.018 M
Work Step by Step
1. Calculate the hydronium ion concentration:
$$[H_3O^+] = 10^{-pH} = 10^{-1.75} = 1.8 \times 10^{-2} \space M$$
2. Since $HNO_3 $ is a strong acid:
$$[HNO_3] = [H_3O^+] = 1.8 \times 10^{-2} \space M = 0.018 \space M$$
