Question

PLEASE HELP! A total of 25.0 mL of 0.150 M potassium hydroxide (KOH) was required to neutralize 15.0 mL of sulfuric acid (H2SO4) of unknown concentration. What is the concentration of the sulfuric acid?

Answer 1

Answer:

2KOH + H₂SO₄ → K₂SO₄ + 2H₂O ; [H₂SO₄] = 0.250 M

NaOH + HBr → NaBr + H₂O , [NaOH] = 0.375M

Explanation:

For the first chart, balanced reaction is:

2KOH + H₂SO₄ → K₂SO₄ + 2H₂O

You must apply the neutralization formula:

M of acid . Volume acid = Volume base . M of base

M of acid . 15 mL = 25 mL. 0.15M

M of acid = (25 mL. 0.15M) / 15 mL → 0.25 M

For the second chart, balanced reaction is:

NaOH + HBr →  NaBr + H₂O

30 mL . 0.250 M = 20 mL . M of base

(30 mL . 0.250 M) / 20 mL = M of base → 0.375 M

Answer 2

Answer:

1) The concentration of H2SO4 is 0.125 M

2) The concentration of NaOH is 0.375 M

Explanation:

Step 1: Data given

Volume of 0.150 M KOH solution = 25.0 mL

Volume of a H2SO4 solution = 15.0 mL

Step 2: Calculate the concentration

bCaVa = aCbVb

⇒ with b = the coefficient of H2SO4 = 1

⇒ with Ca = The concentration of KOH = 0.150 M

⇒ with Va = the volume of KOH = 0.025L

⇒ with a = the coefficient of KOH = 2

⇒ with Cb = The concentration of H2SO4 = ?

⇒ with Vb = the volume of H2SO4 = 0.015L

0.150 * 0.025 = 2*Cb * 0.015

0.00375 = 0.030 *Cb

Cb = 0.125 M

The concentration of H2SO4 is 0.125 M

2)

Step 1: Data given

Volume of 0.250 M HBr solution = 30.0 mL

Volume of a NaOH solution = 20.0 mL

Step 2: Calculate the concentration

bCaVa = aCbVb

⇒ with b = the coefficient of NaOH = 1

⇒ with Ca = The concentration of HBr = 0.250 M

⇒ with Va = the volume of HBr = 0.030 L

⇒ with a = the coefficient of HBr = 1

⇒ with Cb = The concentration of NaOH = ?

⇒ with Vb = the volume of NaOH = 0.020L

0.250 * 0.030 = Cb * 0.020

0.0075 = 0.020 *Cb

Cb = 0.375 M

The concentration of NaOH is 0.375 M