What are the two factors to be considered in choosing an indicator for acid-base titration?

  • Determine the pH of the solution at the equivalence point:
  • Use a table of indicator colour and pH range to choose an indicator which changes colour over a pH range that includes the equivalence point.

What makes a good indicator for titration?

In all cases, though, a good indicator must have the following properties: The color change must be easily detected. The color change must be rapid. The indicator molecule must not react with the substance being titrated.

How is suitable indicator selected for a particular reaction?

In order to determine the accurate end point of acid-base titration, the pH indicator should be selected in such a way that the pH range for the color change of the indicator must coincide with the pH at the equivalent point of reaction.

Why do we use phenolphthalein first then methyl orange?

If you use phenolphthalein, you would titrate until it just becomes colourless (at pH 8.3) because that is as close as you can get to the equivalence point. On the other hand, using methyl orange, you would titrate until there is the very first trace of orange in the solution.

Which is the most commonly used indicator?

The most commonly used indicator in the laboratory is universal indicator. A universal indicator is a pH indicator which shows a pH value ranging from 1 to 14 to indicate the acidity or alkalinity of any solution.

What makes a good indicator?

Reliable: Consistently measured across time and different data collectors. Useful: Can be used for program improvement and to demonstrate program outcomes. Adequate: Can measure change over time and progress toward performance or outcomes. Understandable: Easy to comprehend and interpret.

Why is Methyl Orange a suitable indicator for titration?

Methyl orange is a pH indicator frequently used in titration because of its clear and distinct color variance at different pH values. Methyl orange shows red color in acidic medium and yellow color in basic medium. Because it changes color at the pKa of a mid strength acid, it is usually used in titration for acids.

Why is phenolphthalein a good indicator for Naoh?

Phenolphthalein changes colour at a pH above 7. So it is quite good as an indicator for titrations of strong acids with strong bases. It is also suitable for titrations of weak acids and strong bases, which have an equivalence point at a pH above 7.

What is the difference between phenolphthalein and methyl orange?

Methyl orange and phenolphthalein use as indicator , In Acidic solution Methyl orange gives red colour but in basic solution it gives yellow colour . In Acidic solution phenolphthalein is colourless but in basic it gives pink colour . They both are used as a pH indicator.

Can methyl orange be used first in alkalinity of water?

Examination of m-alkalinity First, the water sample is filtered if it is turbid. Then 3–5 drops of methyl orange solution are added to the water sample (100 mL). Methyl orange has the property to color alkaline and neutral water yellow. If the water becomes acidic, it turns red immediately.

What is the most accurate indicator?

The Bottom Line The STC indicator is a forward-looking, leading indicator, that generates faster, more accurate signals than earlier indicators, such as the MACD because it considers both time (cycles) and moving averages.

What are the 4 types of indicators?

There are four main types of technical indicators: Trend Following, Oscillators, Volatility and Support/Resistance. They are grouped based on their function, which ranges from revealing the average price of a currency pair over time, to providing a clearer picture of support and resistance levels.

How do you make a successful indicator?

  1. Determine your end goal.
  2. Ask key performance questions (KPQs)
  3. Identify what information you already have.
  4. Collect supporting data.
  5. Determine how frequently you’ll measure each KPI.
  6. Set short- and long-term goals for the KPI.

What pH does EDTA titration use?

pH 10 buffer is used in EDTA titration because in EDTA Y4- is predominant, and we want Y4- to react with the metal ions that are present in the titration solution. This can be achieved by using a pH 10 buffer.

Which pH indicator should the scientist use?

1 Answer. You will need an indicator that has a colour change very close to the desired pH. Methyl red or bromcresol green will do for this one.

Which indicator is used for strong acid and weak base?

In the titration of strong acid and weak base, the indicator used is Methyl Orange.

What is the best indicator for HCl and NaOH?

Phenolphthalein is the indicator that is suitable for the titration of HCl and NaOH.

Why is phenolphthalein not a good indicator?

because phenolpthalein changes its colour between pH 8.1-10, and for titration of strong acid and weak base pH is slightly less than 7, so it does not show any change in colour, hence it is not suitable indicator for strong acid – weak base titration.

Why is phenolphthalein a good indicator?

Which indicator is used in acid-base titration? Using a phenolphthalein indicator, a strong acid- strong base titration is performed. Phenolphthalein is selected because it changes colour between 8.3-10 in a pH range. In basic solutions, it will appear pink, and clear in acidic solutions.

Why should you not use universal indicator in titration?

The universal indicator is not used in titration because they have different pH ranges. It becomes difficult to determine the exact pH of the solution. Therefore, universal indicator is not used in titration.

Why do we use phenolphthalein as an indicator in both titrations and not methyl red?

I always used to like phenolphthalein inasmuch as its acidic form is COLOURLESS, and its endpoint is very recognizable from either direction. Phenolphthalein is usually used since it is easy to detect visually a slight pink color from a colorless liquid solution.

At what pH does phenolphthalein turn pink?

Phenolphthalein is naturally colourless and works differently then litmus paper. Also, it turns in pink colour in an alkaline solution or base. Moreover, the compound remains colourless in acids but starts to turn pink on pH 8.2 and continues to turn bright purple in strong bases.

Why methyl orange indicator is not suitable for weak acid strong base titration?

Methyl orange is not suitable for this titration because its pH range lies on the flat portion of the curve.

Why is methyl orange indicator used in HCl and Na2CO3 titration?

Methyl orange changes color in the pH range 3.0 to 4.4 when only one mole of $HCl$ reacts with one mole of sodium carbonate. Phenolphthalein changes color in the pH range of 8.0 to 9.8 when one mole of sodium carbonate is completely neutralized with two moles of $HCl$. Hence the correct option is (B).

Why do we use 2 indicators in alkalinity?

The two indicators are used to determine the alkalinity of a solution as one indicator is used for carbonate and the other is used for bicarbonates.

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