Lable each of the following substances as an acid, base, salt, or none of the above. Indicate whether the substance exists in aqueous solution entirely in molecular form, entirely as ions, or as a mixture of molecules and ions. (a) HF, (b) acetonitrile, CH_3CN, (c) NaClO_4, (d) Ba(OH)_2 What volume of 0, 115 M HCIO_4 solution in needed to neutralize 50.00 mL of 0.0875 M NaOH? (b) What volume of 0.128 M HCI is needed to neutralize 2.87 g of Mg(OH)_2?