Question

What does the 98% solution of \[HN{O_3}\] in water generally refer to?
A. Red fuming nitric acid
B. White fuming nitric acid
C. Green fuming nitric acid
D. Both A and B

Answer 1

Hint:As we know that the Nitric acid also called the spirit of niter has the colourless pure sample but it turns yellow when decomposed into nitrogen oxides and water. $68\% $ concentration of nitric acid in water is commercially available concentration known as the fuming nitric acid.

Complete answer:
As we know that Nitric acid is also known as aqua fortis which means "strong water “ and it is also a spirit of niter which is used for cleaning the wounded skin. Nitric acid in pure form is generally colourless and the older it gets it decomposes to nitrogen oxides and water and turns yellow and these changes that occur can be easily seen in it.
Now, the Fuming nitric acid are in two colours forms which are- Red fuming nitric acid (RFNA), which is about 90% pure and has some dissolved nitrogen oxides which gives it a reddish-brown colour and other one is White fuming Nitric Acid (WFNA) and this substance is present in more than \[98 - 99\% \] pure form.
When the solution contains concentration more than 98% in water it is called as white fuming nitric acid.

Therefore, option (B) is the correct answer that is \[98\% \] solution of \[HN{O_3}\] in water is generally referred to White fuming nitric acid.

Note:
White fuming nitric acid (WFNA) is used as a storable liquid oxidizer and along with red fuming nitric acid it is used in liquid fuelled rockets. It consists of nearly pure nitric acid. WFNA has a maximum of $2\% $ water and \[0.5\% \] dissolved nitrogen dioxide whereas Red Fuming Nitric Acid is commonly specified as containing no more than $2\% $ water and less than \[0.5\% \] dissolved nitrogen dioxide or dinitrogen tetroxide.