The swimming pools pH is below 7, meaning it is slightly acidic. If you want to make the pH higher, you must add a base which by definition has a pH higher than 7.
D. Add base
Answer: Because hydrogen is a gas.
Explanation: If children were running around with balloons filled with hydrogen gas, then they would catch fire. So the answer to your question is, its simply dangerous.
Explanation:
a.
→ ?




Removing common ions from both sides, we get the net ionic equation:

b.
→

No precipitation is occuring.
c.
→




Removing common ions from both sides, we get the net ionic equation:

d.
→




Removing common ions from both sides, we get the net ionic equation:

The alcohol concentration of the mixed solution is 20%
Simplification :
Based on the given condition, formulate :
35% ×0.40 + 0.6 ×10% ÷{ 0.4+0.6}
Calculate the product :
Calculate the sum or difference : 
Any fraction with denominator 1 is equal to numerator : 0.2
Multiply a number to both numerator, denominator : 0.2 ×
Calculate the product or quotient : 
A fraction with denominator equals to 100 to a percentage 20%.
How do you find the concentration of a mixed solution?
In general when your are mixing two different concentrations together first calculate number of moles for each solution (n=CV ,V-in liter) then add them together it will be total moles,then concentration of mixture will be = total moles / total volume(liter).
Learn more about concentration of alcohol :
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