Close

2021-06-17

How does an acid-base indicator react when placed in an acidic solution?

How does an acid-base indicator react when placed in an acidic solution?

Explanation: An acid-base indicator is an indicator which changes color according to the pH of solution in which it is placed. Thus, we can conclude that out of the given options, an acid–base indicator react by changing color when placed in an acidic solution, is the correct option.

How do acid-base indicators change color?

The color change of a pH indicator is caused by the dissociation of the H+ ion from the indicator itself. Recall that pH indicators are not only natural dyes but also weak acids. The dissociation of the weak acid indicator causes the solution to change color.

Do indicators change the color of acids?

When universal indicator is added to a solution, the color change can indicate the approximate pH of the solution. Acids cause universal indicator solution to change from green toward red. Bases cause universal indicator to change from green toward purple.

What causes color change in titration?

As the EDTA solution is added, the concentration of the metal ion in the solution decreases due to the formation of metal-EDTA complex. At the end point no more free metal ions are present in the solution. At this stage, the free indicator is liberated and hence the colour changes from red to blue.

Why pH is maintained in complexometric titration?

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 type of buffer solution is used in complexometric titration?

EDTA, often written as H4Y , is a common ligand in complexometric titrations. It has four carboxyl groups and two amine groups that can act as electron pair donors (Lewis bases). EDTA is often used as the disodium salt, Na2H2Y . Carrying out the reaction in a basic buffer solution removes the H+ as it is formed.

Which buffer solution is used in EDTA method?

Total hardness On addition of EDTA solution, Ca2+/Mg2+ ions preferably forms a stable EDTA- Ca2+/Mg2+ complex with EDTA leaving the free EBT indicator in solution which is steel blue in colour in the presence of ammonia buffer (mixture of ammonium chloride and ammonium hydroxide, pH 10).

What is the pH of the buffer solution?

A buffer solution is one which resists changes in pH when small quantities of an acid or an alkali are added to it. An acidic buffer solution is simply one which has a pH less than 7. Acidic buffer solutions are commonly made from a weak acid and one of its salts – often a sodium salt.

How do you know if a buffer is acidic?

To calculate the specific pH of a given buffer, you need to use the Henderson-Hasselbalch equation for acidic buffers: “pH = pKa + log10([A-]/[HA]),” where Ka is the “dissociation constant” for the weak acid, [A-] is the concentration of conjugate base and [HA] is the concentration of the weak acid.

How a buffer solution will resist the change in the pH if a small amount of acid is added into it?

A buffer solution usually contains a weak acid and its conjugate base. Similarly, when OH– is added, the weak acid will donate a proton (H+) to its conjugate base, thereby resisting any increase in pH before shifting to a new equilibrium point.

Which of the following is an example of a strong base?

Examples of Strong Bases

Base Formula Ions
sodium hydroxide NaOH Na+(aq) + OH-(aq)
potassium hydroxide KOH K+(aq) + OH-(aq)
lithium hydroxide LiOH Li+(aq) + OH-(aq)
rubidium hydroxide RbOH Rb+(aq) + OH-(aq)

What are strong and weak bases give example?

Strong base: BOH + H2O → B+(aq) + OH-(aq) Examples of strong acids and bases are given in the table below. In aqueous solution, each of these essentially ionizes 100%. A weak acid or a weak base only partially dissociates.