Answer:
E) 2.38
Explanation:
The pH of any solution , helps to determine the acidic strength of the solution ,
i.e. ,
- Lower the value of pH , higher is its acidic strength
and ,
- Higher the value of pH , lower is its acidic strength .
pH is given as the negative log of the concentration of H⁺ ions ,
hence ,
pH = - log H⁺
From the question ,
the concentration of the solution is 0.0042 M , and being it a strong acid , dissociates completely to its respective ions ,
Therefore , the concentration of H⁺ = 0.0042 M .
Hence , using the above equation , the value of pH can be calculated as follows -
pH = - log H⁺
pH = - log ( 0.0042 M )
pH = 2.38 .
Answer: The standard free energy change for a reaction in an electrolytic cell is always positive.
Explanation:
Electrolytic cells use electric currents to drive a non-spontaneous reaction forward.
Relation of standard free energy change and emf of cell

where,
= standard free energy change
n= no of electrons gained or lost
F= faraday's constant
= standard emf
= standard emf = -ve , for non spontaneous reaction
Thus 
Thus standard free energy change for a reaction in an electrolytic cell is always positive.
Answer:
The amount of dissolved gases in the body. Have a good day! =)
Explanation:
Looking at the information given above, you will notice that, for cancer disease, the patient was sure that his parents and aunts did not have the disease condition but it does not know whether his grand parents and uncles have it or not. Therefore, he will have to find out more about history of cancer in the family.
For heart disease condition, his parents and uncles have heart problems. Because of this, the patient has to undergo preventative care for heart disease.
For diabetes condition, his grand parents have diabetes and he also thinks that his aunts have. Due to this fact, the patient also have to receive preventative care for diabetes.