Question

Could someone answer the following questions?

1) 11.2 g of potassium hydroxide (KOH) is dissolved in sufficient water to make 1 L of solution. What is the concentration of KOH in the solution?

	a.	0.02 mol/L
	b.	0.1 mol/L
	c.	0.2 mol/L
	d.	0.01 mol/L

2) If the solution is neutral, which of the following must be true?

	a.	[OH-] = [H2O]
	b.	[H+] > [OH-]
	c.	[H+] < [OH-]
	d.	[H+] = [OH-]

3)A student titrates 0.5222 grams of KHP (potassium hydrogen phthalate; MW = 204.2 g/mol) to the equivalence point with 24.08 mL of NaOH (aq). The concentration of the NaOH is:

	a.	0.1722 M
	b.	1.722 x 10-4 M
	c.	0.09722 M
	d.	9.416 M
	e.	0.1062 M

4)During your standardization experiment, you measured 0.0521 grams of potassium hydrogen phthalate (Molar Mass = 204.22 g/mol) which required 24.12 mL of your sodium hydroxide standard to reach the endpoint. What is the concentration of your sodium hydroxide standard solution?

	a.	0.0106 M
	b.	1.06 x 10-5 M
	c.	0.0441 M
	d.	0.441 M

Answer 1

Ans 1. Moles of KOH wt. of KOH in grams/ Molar mass of KOH Molar mas of KoH- 39-17-56 g/mol because K- 30 g/imol and O-17 g/mol Now KOH weight is given in question 11.2 grams Therefore, moles of KOH-11.2g/56g/mol= 2.2 moles Now Molarity - # of moles/litre(L) of solution Here we have 0.2 moles of KOH as calculated above and 1 litre(L) of solution Therefore. Molarity or concentration of KOH 0.2mol/1 litres- 0.2mol/L Therefore option (c) is correct

ers.pdl Adobe Aciobat Reader De Window Help 116% A neutral sdlution has a balance between the H+ and the OFl-ions and it has a phl of 7 Therefore, a neutral solution has [H+] [OH-]. The option (d) is correct

Wed Answers.pdf 1 1 2 116% Ans 3. Calculating the moles of KHP (potassi um hydrogen phthalate)-0.5222 g (mol/204.2g) 0.002557 mol KHP 0.002557 mol NaOH is required to titrate 0.002557 mol KHP The concentration of NaOHIi 0.002557 mol (1/24.08 ml) (1000 ml/L)-0.1062M Option (e) is correct

Ans 4. calculating the moles of KHP (potassium hydrogen phthalate) 0.0521 g ( 0.00025511 moi КНР 0.00025511 mol NaOH is required to titrate 0.00025511 mol KHP The concentration of NaOH is 0.0002551 l mol (I/24. I 2ml) (1000 ml/L) = 0.0106M Option (a) is correct