An aqueous solution contains 0.30 M hypochlorous acid. One Liter of this solution could be converted into a buffer by the addition of: (Assume that the volume remains constant as each substance is added.) 0.31 mol KClO 0.30 mol KBr 0.15 mol HCl 0.074 mol Ca(OH)2 0.31 mol HCl

Explanation:

Every buffer system comprises of a weak acid or a base and its salt. The pH of the resultant buffer is calculated by the Henderson-Hassel Bach equation as pH = pKa + log ([Salt]/[Acid]). Thus, a hypochlorous acid buffer should also contain a salt of hypochlorous acid, which among given is potassium hypochlorite (KClO). Potassium perchlorate on the other hand does not function as a buffer, as the counter ion by perchloric acid is not present, preventing common ion effect from arising for the perchlorate anion.

Nitric acid and sodium hydroxide are strong acid and base. Hence, they will not undergo partial ionization required for equilibrium adjustment necessary in a buffer. In a buffer, the partial ionization of the parent acid or base is essential as it is that factor that helps the buffer maintain pH during acid or base addition by simply increasing or decreasing the parent acid/base's ionization depending upon the excess quantity of proton of hydroxyl ions present. Such a reversible dissociation however is not possible in strong acids and bases rendering them useless as buffer components.

Therefore, among the given chemicals, 0.31mol KClO can be added to a liter of 0.3M HClO to afford a buffer.

mechanics (greek   is that area of science concerned with the behaviour of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment. the scientific discipline has its origins in ancient greece with the writings of aristotle and archimedes[1][2][3] (see history of classical mechanics and timeline of classical mechanics). during the early modern period, scientists such as galileo, kepler, and newton laid the foundation for what is now known as classical mechanics. it is a branch of classical physics that deals with particles that are either at rest or are moving with velocities significantly less than the speed of light. it can also be defined as a branch of science which deals with the motion of and forces on objects. the field is yet less widely understood in terms of quantum theory.

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