<u>Answer:</u> The volume of concentrated hydrochloric acid required is 16.53 mL
<u>Explanation:</u>
To calculate the volume of concentrated solution, we use the equation:

where,
are the molarity and volume of the concentrated solution
are the molarity and volume of diluted solution
We are given:
Conversion factor: 1 L = 1000 mL

Putting values in above equation, we get:

Hence, the volume of concentrated hydrochloric acid required is 16.53 mL
Answer:
There are 4 tryptophans in the protein.
Explanation:
According to question, protein contains one tyrosine residue and say x number of tryptophans.
Concentration of protein solution = 1.0 micromolar = 
Molar absorptivity of a protein solution : 


Length of the cuvette = l = 1.0 cm
Absorbance of protein solution at 280 nm = A = 0.024
( Beer-Lambert's law)

Solving for x :
x = 4
There are 4 tryptophans in the protein.
The yield of lithium chloride is 1.92 grams.
Option D.
<h3><u>Explanation:</u></h3>
In this reaction, we can see that 1 mole of lithium hydroxide reacts with 1 mole of potassium chloride to produce 1 mole of lithium chloride and 1 mole of potassium hydroxide.
Molecular weight of lithium hydroxide is 24.
Molecular weight of lithium chloride is 42.5.
So 24 grams of lithium hydroxide produces 42.5 grams of lithium chloride.
So, 20 grams of lithium hydroxide produces
grams =11. 29 grams of lithium chloride.
But this is when the yield is 100%.
But yield is 17%.
So the yield is 1.92 grams of lithium chloride.
Balanced there are 2 Al, 6 oxygens on both sides.