A solution has [OH-]=3.5*10^-6. Based on that, what must be true about this solution?

Option B. It is a basic solution.

Explanation:

To know which option is correct, let us calculate the pH of the solution.

First, we shall determine the pOH of the solution. This is illustrated below:

Concentration of Hydroxide ion, [OH¯] = 3.5×10¯⁶

pOH =.?

pOH = –Log [OH¯]

pOH = –Log 3.5×10¯⁶

pOH = 5.5

Finally, we shall determine the pH. This can be obtained as follow:

pOH = 5.5

pH =?

pH + pOH = 14

pH + 5.5 = 14

Collect like terms

pH = 14 – 5.5

pH = 8.5

The pH scale reads as follow:

0 to 6 => Acidic

7 => Neutral

8 to 14 => Basic

Comparing the pH of the solution (i.e 8.5) with the pH scale, we can conclude that the solution is basic because the pH of solution lies between 8 and 14.

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