Compare the solubility of mn(oh)2 (ksp = 1.6x10-13)in the following solutions: pure water, a solution buffered to be ph = 6.5 a solution buffered to be ph = 3.5 compare the solubility of mn(oh)2 (ksp = 1.6x10-13)in the following solutions: pure water, a solution buffered to be ph = 6.5 a solution buffered to be ph = 3.5 pure water > ph 3.5 > ph 6.5 (least soluble) ph 3.5 > ph 6.5 > pure water (least soluble) ph 3.5 > pure water > ph 6.5 (least soluble) pure water > ph 6.5 > ph 3.5 (least soluble) ph 6.5 > ph 3.5 > pure water (least soluble)

The order will be:

pH 3.5 > pH 6.5 > pH 7

Explanation:

The solubility equation for Mn(OH)₂ is:

As per the reaction, Mn(OH)₂ is giving hydroxide ions

The given conditions are

a) Pure water = here the pH of water is 7.

[OH⁻] = 10⁻⁷ M

b) pH = 6.5

pOH = 7.5

[OH⁻] = 3.16 X 10⁻⁸ M

c) pH = 3.5

pOH = 10.5

[OH⁻] =3.16 X  10⁻¹¹ M

Thus from the three solutions and water the maximum concentration of hdyroxide ion is in pure water, hence the Mn(OH)₂ will be least soluble in it.

More the concentration of hydroxide, lesser the solubility of Mn(OH)₂

Order will be

pH 3.5 > pH 6.5 > pH 7

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.