# ::::: pH ::::::?

Question:Justify the following statements without much of calculations :-

1> pH of 10^(-8) molal HCl is Around 6.96
2> pH of 10^(-8) molal NaOH is Around 7.04
3> pH cant be negative

1> pH of 10^(-8) molal HCl is Around 6.96
10^(-8) is such a small concentration of H+ ions that there is nearly no impact of such. Assuming you made a type and "molal" means "molarity", molarity is given by the equation:

molarity = mols / volume

by which mols of H+ are divided by the total volume of the solution. In molarity, your basic solution comprises of H2O and whatever is being diluted by the water, in this case, HCl. On a pH scale, the lower the pH, the more acidic the solution is while the higher the pH, the more basic the solution becomes. Because HCl is broken up into H+ and Cl- ions, there are free floating H+ ions which make HCl acidic.

H2O has a pH of 7.0 and when combined with the almost negligible concentration of HCl, causes the overall solution's pH to drop minutely from 7.0 to around 6.96

2> pH of 10^(-8) molal NaOH is Around 7.04
This question is just like the first question, however, NaOH breaks apart into Na+ and OH- ions. Because of the presence of free floating hydroxide ions (OH-), the solution is basic.

For all the same reasons as question #1, the 7.0 pH of water is only minimally affected by the small concentration of OH- ions in NaOH that it's overall pH will only rise a little from 7.0 to around 7.04

3> pH cant be negative
This is true. The pH scale goes from 1.0 to 14.0 where 1 is very acidic, 6 is weakly acidic, 7 is neutral, 8 is weakly basic, and 14 is strongly basic.

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