Please help, I need this really soon.

What substance is the most acidic. lemon juice. tomato juice. sodium hydroxide. water

Once an egg cell is fertilized by sperm, the cell then, as the embryo develops, it receives nourishment and eliminates wastes by transferring substances from its blood to its mother's blood. a. becomes a fetus immediately and exits the womb b. begins to divide and implants itself in the wall of the uterus c. remains in the uterus without dividing for several months d. travels back to the ovaries until the fetus is developed

For each of the formulas, classify the formula as either an empirical formula, a molecular formula, or both. nahco3 empirical molecular both