Hydrogen iodide (HI) Molar Mass (With Calculations)

Hydrogen iodide (HI) Molar Mass

Molar mass of HI (Hydrogen iodide) is 127.908 g/mol.

Well, now you have come to know the molar mass of HI.

But how can you get this value?

Let me show you the calculation to get the molar mass of HI ( Hydrogen iodide).

If you are a visual learner like me, then here is a short one minute video for you.

HI (Hydrogen iodide) Molar Mass Calculation

If you have a periodic table with you, then you can easily calculate the molar mass of HI (Hydrogen iodide).

Because the molar mass of any molecule (or compound) can be calculated by simply adding the molar masses of individual atoms.

Now here we have to find the molar mass of HI (Hydrogen iodide).

So for that, have a look at the periodic table given below.

You can see the molar mass value of all the atoms from this periodic table.

Now in HI, there is 1 Hydrogen atom and 1 Iodine atom.

So let’s look at the molar mass of Hydrogen and Iodine from the above periodic table.

You can see that;

The molar mass of Hydrogen is 1.008 g/mol. [1]

The molar mass of Iodine is 126.90 g/mol. [2]

Now, to calculate the molar mass of HI, you just have to add the molar mass of all the individual atoms that are present in HI.

You can see that in HI, there is 1 Hydrogen atom and 1 Iodine atom.

So, Molar mass of Hydrogen iodide (HI) = Molar mass of 1 Hydrogen (H) atom + Molar mass of 1 Iodine (I) atom.
= 1.008 + 126.90
= 127.908 g/mol

Hence the Molar mass of HI is 127.908 g/mol.

I hope you have understood the short and simple calculation for finding the molar mass of HI.


  • In some books, you may see the unit of molar mass as grams/mole or g/mole. But all these units (i.e g/mol, grams/mole and g/mole) are the same. 
  • Always follow the calculation order to avoid any mistakes in calculation. First solve the brackets, then multiplications and at last do the final addition.
  • And don’t forget to put the unit g/mol to your final calculated molar mass.

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Jay is an educator and has helped more than 100,000 students in their studies by providing simple and easy explanations on different science-related topics. With a desire to make learning accessible for everyone, he founded Knords Learning, an online learning platform that provides students with easily understandable explanations.

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