Question

Which of the following statements about hydrogen is correct?
A. Hydrogen has three isotopes of which tritium is the most common
B. Hydrogen never acts as cation in ionic salts
C. Hydronium ion, ${H_3}{O^ + }$ exists freely in solution
D. Dihydrogen does not act as a reducing agent

Answer 1

Hint: Hydrogen is the first element of the periodic table with one electron in its shell and it acts as an anion. This diatomic gas has three isotopes which generally act as reducing agents while performing certain chemical reactions.

Step by step answer: To answer this question we need to have detailed knowledge of hydrogen.
Hydrogen is the chemical element with symbol H and atomic number 1. It is the lightest element in the periodic table with a standard atomic weight of 1.008. It is the most abundant chemical substance in the universe. Hydrogen has three isotopes namely protium, deuterium and tritium with percent abundance of $99.985$ , $0.0156$ and ${10^{ - 15}}$ respectively. Therefore, the most common isotope of hydrogen is protium and has one proton and no neutrons.
At standard temperature and pressure hydrogen is a colourless, odourless, tasteless, non-toxic, non-metallic and highly combustible diatomic gas with the molecular formula ${H_2}$ . It readily forms covalent compounds with other compounds, mostly non-metallic elements. It exists on earth mostly in molecular forms such as water or organic compounds.
Hydrogen gas was first artificially produced in the early 16th century by the reaction of acids on metals. Then it was found out that it was a discrete substance and it produces water when burned and therefore it was later named as “water-former”.
Now, moving to the options one by one we will find the incorrect one. According to the first option tritium is most common which is wrong. From the above information we know that the first option is incorrect.
According to the second option hydrogen never acts as cation in ionic salts. This statement is correct. For example $NaH$ is an ionic salt and it never acts as cation in it but is an anion.
According to the third option hydronium ion exists freely in solution. This statement is also correct as it is found moving freely in solutions.
According to the fourth option dihydrogen does not act as a reducing agent. This statement is wrong as it acts as a reducing agent as it reduces the element which reacts with it.

Therefore, options A and D are incorrect and B and C are correct. So, according to the question, our answer is B and C.

Note: Hydrogen is one of the most important elements and is present in every compound and reacts with every compound. Due to its light weight it is found in abundance. This “water-former” is commonly used in industrial production.