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Physical change is a type of change where the physical properties of matter change. A change of state of matter, change in colour, odour, solubility, etc. all are examples of physical change. During a physical change, neither the composition nor the chemical nature of matter is changed.
- Law of Conservation of Mass
Law of Conservation of Mass Questions and Answers - Practice...
- Law of Conservation of Mass
A pH indicator, also known as an acid-base indicator, is a compound that changes colour in solution over a narrow pH range. To produce a visible colour change, only a small amount of indicator compound is required.
- The dissociation of the H+ ion from the indicator itself causes the colour change of a pH indicator. Remember that pH indicators are both natural d...
- The charge state of the solute can be changed by varying the pH of the solution. When the pH of a solution is such that a specific molecule carries...
- A universal indicator is a liquid/solution substance that is dropped into a sample and changes the substance according to the pH. pH paper is an in...
- The pH scale ranges from 0 to 14, with- pH below 7 is considered acidic pH above 7 is considered basic pH = 7 neutral, depending on the concentrati...
- While pH metres and pH paper are portable methods for measuring the pH of a solution, pH metres provide more accurate results. Colour blindness is...
Jan 30, 2023 · Indicators are substances whose solutions change color due to changes in pH. These are called acid-base indicators. They are usually weak acids or bases, but their conjugate base or acid forms have different colors due to differences in their absorption spectra.
- Apparatus of Titration
- Theory of Acid Base Indicators
- Ph at The End Point of Acid – Base Titration
- Titration Curve
- Selection of A Suitable Indicator
- Colour Change Pkindicator =PH at The Equivalence Point
- Ph Range of 2 Units of Indicators
- Calculation of Pka PR PKB Values from Ph of Equivalence Point
- Calculation of Volumetric Analysis
Procedure 1) A known volume of the solution is taken in the titration flask with the help of a pipette. 2) The other solution is taken in the burette which is graduated in cc’s and has a stop cock at bottom to control the amount of flow into the flask. 3) The solution to be titrated is taken in the flask and is called titrate and the solution with ...
Acid base indicatorsare mostly complex organic molecules which are either weak acid or weak bases For ex: Phenolphthalein is a weak organic acid (HPh) and methyl orangeis a weak organic base ( MeOH) . Phenolphthalein and methyl orange dissociates in aqueous solution as : HPh H++ Ph‾ ————— (1) colourless pink MeOH Me++ OH‾ ————–(2) Yellow red colour...
(1) If strong acid has been titrated with strong base, the pH at the end point is 7. (2) If a weak acid or a weak base is involved in the titration, pH at the end point depends upon the hydrolysis of salt formed.In any type of acid-base titration, it is found that there is a sudden change in the pH value at the end. As the titration proceeds, if th...
The point at which there is sudden change in pH when a very small amount of titrant is added to the titrate is called point of inflection. The steepness of the slope around the equivalence point is quite large in case of titration of strong acid against strong base whereas it is less steep if the acid or base is weak. Large steepness means large ch...
The indicator used should be such that it shows change in colour in the same pH range as required around the equivalence point. (1) For titration of a strong acid against a strong base, any indicator out of methyl orange, methyl red, phenolphthalein or bromothymol blue can be used to determine the endpoint. (2) For titration of weak acid like aceti...
Consider an indicator which is a weak organic acid.Let it be represented by HIn. In aqueous solution , it dissociates as: HIn (aq) H+(aq) + In‾ (aq) HIn and In‾ have different colours.The equilibrium constant for the above reaction is : KIn = [H+] [In‾ ] / [HIn] The exact point of colour change will be at the pH when [HIn] = [In‾ ] KIn = – log kIn ...
Most of the indicators have a useful colour change over a pH range of 2 units. For Ex: Phenolphthalein , change from colourless to pink in the pH range of 8.3 to 10. For an indicator HIn HIn ( aq) H+(aq) + In‾ (aq) KIn = [H+] [In‾ ] / [HIn] Acidic colour [In‾ ] / [HIn] = 1 / 10 Alkaline colour [In‾ ] / [HIn] = 10/1 [H+] = { [HIn] / [In‾ ] } KIn For...
For a weak acid , HA HA H++ A‾ Ka ={ [ H+ ] [ A‾ ] } / [HA ] [ H+ ] = { [HA ] / [ A‾ ] } / Ka – log [ H+ ] = – log Ka – log [HA] / [A‾ ] pH = pKa – log [HA] / [A‾ ] The half equivalence point is the point in the neutralisation at which one half of HA has been neutralised in the reaction: HA + OH‾ H2O + A‾ At this point, [HA] = [A‾ ] pH = pKa – log ...
Suppose the two reactants involved are A and B. Suppose V1 cc of the solution of reactant A having normality N1 exactly with V2 cc of the solution of reactant B having normality N2. Number of gram equivalent of A reacted = N1 × V1/ 1000 Number of gram equivalent of B reacted = N2 × V2/ 1000 As the reactants react in equivalent amount , N1 × V1 / 10...
Aug 12, 2022 · Chemical changes are frequently harder to reverse than physical changes. Observations that indicate a chemical change has occurred include color change, temperature change, light given off, formation of bubbles, formation of a precipitate, etc.
Souring of milk is a change. Stretched rubber band also represents a change. Make a list of ten changes you have noticed around you. In this chapter we shall perform some activities and study the nature of these changes. Broadly, these changes are of two kinds, physical and chemical. Fig. 6.1 Paper pieces. 6.1 PHYSICAL CHANGES. Activity 6.1.
A glass electrode and pH metre, or colour-changing indicator, may be used to measure the pH of aqueous solutions.
