Answer:- pH is 2.14.
Solution:- Nitrous acid, 
is a weak acid so first of all we solve for 
and then figure out the pH.
the equation is written as:
Initial concentration for the acid is given as 0.120 M. Let's say the change in concentration is x. Then the equilibrium concentrations would be as:
= 
=
Ka for nitrous acid is 
and the equilibrium expression for this would be written as:
![Ka=\frac{[H_3O^+][NO_2^-]}{HNO_2}](https://tex.z-dn.net/?f=Ka%3D%5Cfrac%7B%5BH_3O%5E%2B%5D%5BNO_2%5E-%5D%7D%7BHNO_2%7D)
Let's plug in the values in it.
To make the calculations easy we could ignore for the bottom and the expression becomes:
On cross multiply:
On taking square root to both sides:
So, ![[H_3O^+]=7.3*10^-^3M](https://tex.z-dn.net/?f=%5BH_3O%5E%2B%5D%3D7.3%2A10%5E-%5E3M)
Now we could calculate the pH using the pH formula:
![pH=-log[H_3O^+]](https://tex.z-dn.net/?f=pH%3D-log%5BH_3O%5E%2B%5D)
pH = 2.14
So, the pH of 0.120M nitrous acid is 2.14.
0.2M means 0.2mol CaCl2/1L solution.
This question didn't give us a density of the solution so needs an assumption that the solution has equal volume to water.
xmol/0.5L=0.2M
x = 0.1
0.1mol of CaCl2 is needed. Ca=40g/mol, Cl=35.5g/mol.
CaCl2 0.1mol = (40+35.5*2)*0.1=11.1g
The pH of the buffer that consists of 0.55 M HNO₂ is 3.3, which is acidic.
<h3>
What is the common name for 0.55 M HNO₂?</h3>
The common name for 0.55 M HNO₂ is Nitrous acid. Only in solution, the gas phase, and in the form of nitrite salts is nitrous acid, a weak and monoprotic acid, known to science. Amines are converted into diazonium salts using nitrous acid. To produce azo colors, azo coupling processes use the resultant diazonium salts as reagents. A nitrogen oxoacid is a nitrous acid. It is a nitrite's conjugate acid. To treat cyanide poisoning, sodium thiosulfate is combined intravenously with nitrous acid (as sodium nitrite).
To learn more about Nitrous acid, visit:
brainly.com/question/17055219
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Answer:
Object 1 = Moving Towards Earth
Object 2 = Moving Away From Earth
Object 3 = Moving Towards Earth
Explanation:
When you look at emission spectras, look at where the observed lines are in comparison to the element (stationary) lines. Ones that have observed lines closer to the left are moving towards you and ones with observed lines closer to the right are moving away from you.
