science

What indicates that a titration is finished?

When the solution changes color and the new color persists for at least 30 seconds (endpoint reached).

What color change occurs with phenolphthalein in titration?

It changes from colorless (acidic) to light pink (basic).

What color change occurs with bromophenol blue?

It changes to a light gray color at the endpoint.

What is titration?

A quantitative method used to determine the unknown concentration of a solution by reacting it with a solution of known concentration.

What is the role of an indicator in titration?

It shows the endpoint by changing color depending on the pH.

What is hydrochloric acid (HCl)?

A strong acid that forms when hydrogen chloride gas dissolves in water.

What is sodium hydroxide (NaOH)?

A strong base that is highly soluble in water and very caustic.

What is the neutralization reaction between HBr and LiOH?

HBr + LiOH → H₂O + LiBr

What is the equivalence point?

The point where the amount of acid equals the amount of base in a titration.

Why might phenolphthalein and bromophenol blue give different results?

Because they change color at different pH ranges, not exactly at the equivalence point.

What is the calculated concentration of HCl using bromophenol blue?

0.003567 M

How do you calculate concentration in titration?

Use the formula:
M₁V₁ = M₂V₂

Solve: What is the concentration of HBr if 10.00 mL is neutralized by 16.73 mL of 0.253 M LiOH?

0.151 M

Why is bromothymol blue a better indicator for neutralization at pH 7?

Because its color change occurs around pH 7, matching the equivalence point.