Answer:125ml - volume of phosphoic acid
Explanation:
The equation of the reaction is
H3PO4 + 3 NaOH ---> Na3PO4 + 3H2O
Such that I mole of H3PO4 reacts with 3 moles of NaOH to produce the products above.
Given that
M1= Molarity of phosphoric acid = 7.48x10^-2 M
n1= number of moles of phosphoric acid = 1
V1=? ml
M2= Molarity of Sodium hydroxide =0.244 M
V2= volume of sodium hydroxide= 115ml
n2=number of moles of sodium hydroxide = 3
Using the Dilution equation formulae,
M1V1/n1 = M2V2/n2
7.48X10-2 x V1 /1= 0.244M x 115ml/3
V1=0.244Mx115mlx1/0.0748M X 3
V1= 28.06/0.2244= 125.04ml
V1=125.04ml rounded up to 125ml
The correct answer is 0.44ml
For information, promethazine is a neuroleptic antihistamine inhibitor of H1 receptors of the phenothiazine family. It is a medicine used in the treatment of allergy (like rhinitis) and transient insomnia.
To respond to this exercise, it is necessary to cross-multiply.
In the antihistamine bottle solution:
25 mg corresponds to 1 ml
11 mg corresponds to: 11/25 = 0.44 ml of the solution.
This 0.44ml is taken from the bottle and put to the syringe.
Here are the list of nucleo bases : adenine , Thymine, Guanine , Cytosine
Adenine pairs with Thymine, and Guanine pairs with Cytosine
Adenine + Guanine = Purine
Thymine + Cytosine = Pyrimidine
So the answer for number 1 will be : Purine, since Adenine is not the choice
And the answer for number 2 is Guanine
hope this helps
