Answer:
c.I ,II & IV are correct
Explanation:
Phenolphthalein is an indicator. An indicator is an organic dye whose solution changes colour as the concentration of hydrogen ions in solution changes.
Hence a typical indicator exhibits different colours at different pH ranges. The colour of an indicator in an acid, a base and at end point always differs.
Phenolphthalein is a colourless solution which has a pink colour in an alkaline medium and colourless in an acidic medium.
Work is the use of force to move an object. It is directly related to both the force applied to the object and the distance the object moves. Work can be calculated with this equation: Work = Force x Distance.
Explanation:
The reaction is exothermic because the total bond energy of the reactants is less than the total bond energy of the products is true about change in bond in Exothermic reaction.
<h3>What is an Exothermic reaction?</h3>
An Exothermic reaction in thermodynamics is a type of reaction that released energy from the system of reaction to it's surroundings which can be inform of light, heat or even electricity or sound.
Exothermic reaction has net negative standard enthalpy change.
Therefore, The reaction is exothermic because the total bond energy of the reactants is less than the total bond energy of the products is true about change in bond in Exothermic reaction
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Planck suggested that light/energy was absorbed/released in certain amounts, called quanta.