16 What is the oxidation number of P in PO4 17 What volume o

16. What is the oxidation number of P in PO4. 17. What volume of a 0.200 M solution of NaCI contains 53.0 g of NaC1? 18. What volume of a 5.00 M NaCI solution should be diluted to make 750. mL of a 0.5 solution? 19. Calculate the molarity of a solution that contains 10.0 g of NH3 in 750.0 mL of so

Solution

16)

PO₄^- actually means (PO)₄^-

So, the overall charge of PO₄^- = -1

Oxidation state of oxygen = -2

And there are 4 Oxygen(O).

Let oxidation state of P be x,

Then,

x + (-2 * 4) = -1

x – 8 = -1

x = +7

Therefore oxidation state of P in PO₄^- is +7.

17)

The molar mass of NaOH = 58.34 g / mol.

No. of moles of NaOH = mass of NaOH / molar mass of NaOH

                                   = (53 g) / (58.45 g/mol)

                                   = 0.9067 mol

Therefore, volume of NaOH = moles of NaOH / given moles per litre

                                           = (0.9067 mol) / (0.2 mol/L)

                                           = 4.5335 L.

Volume of NaOH for given condition is 4.5335 L.