I think the correct answers from the choices listed above are the first, third and the last option. Ionic compounds are compounds that dissociates into ions when in aqueous solution. From the list, NH4Cl, KF and MgO are the ionic compounds. Hope this answers the question.
Answer : The volume of 3.0 M spinach solution added should be, 50 mL
Explanation :
Formula used :

where,
are the initial molarity and volume of spinach solution.
are the final molarity and volume of diluted spinach solution.
We are given:

Now put all the given values in above equation, we get:

Hence, the volume of 3.0 M spinach solution added should be, 50 mL
Explanation:
Atoms never gain protons; they become positively charge only by losing electrons. A positive ion is called a cation (pronounced: CAT-eye-on). You may have notice that the number of neutrons in each of these ions was not specified.
Answer: The answer is 2.3 x 10 4's.
C. 2Fe2O3 would be the correct answer!