Final answer:
Citric acid gives off H+ ions, being a polyprotic acid capable of donating more than one proton per molecule when dissolved in water. Option 1 is correct.
Step-by-step explanation:
Among the options presented, citric acid gives off H+ when it dissociates in water. Citric acid is a weak polyprotic acid, meaning it can donate more than one proton (H+) per molecule. When citric acid dissolves in water, it undergoes a stepwise ionization process where protons are released into the solution, thus increasing the concentration of hydronium ions (H3O+).
Unlike what is suggested by option 2 (OH−) and option 4 (H2O), these are not protons but a hydroxide ion and a water molecule, respectively. Option 3 (H3O+) represents the hydronium ion, which is produced when an acid donates a proton to water, but it is not the proton given off.