Consider the following statements regarding a motor car battery: 1. I. The voltage is usually 12 V. 2. II. Electrolyte used is hydrochloric acid. 3. III. Electrodes are lead and copper. 4. IV. Capacity is expressed in ampere-hour. Which of the above statements are correct?

1. Statement I: The typical voltage of a motor car battery (lead-acid battery) is indeed 12 V (composed of six 2V cells connected in series). This statement is correct. 2. Statement II: The electrolyte used in a lead-acid battery is dilute sulfuric acid (H2SO4), not hydrochloric acid (HCl). This statement is incorrect. 3. Statement III: The electrodes in a lead-acid battery are typically made of lead (Pb) for the negative electrode and lead dioxide (PbO2) for the positive electrode, not lead and copper. This statement is incorrect. 4. Statement IV: The capacity of a battery, indicating how much charge it can deliver, is commonly expressed in ampere-hour (Ah). This statement is correct. 5. Therefore, statements I and IV are correct.