ANS:A - basic

The pH of a solution is a logarithmic measure of the hydrogen ion concentration (𝐻+H+). Each unit change in pH represents a tenfold change in 𝐻+H+ concentration. Given that the pH value of the solution is 5.9, we know that: pH=−log⁡[𝐻+]pH=−log[H+] So, if the hydrogen ion concentration is decreased hundred times, the new hydrogen ion concentration would be: [𝐻+]new=1100×[𝐻+]old[H+]new​=1001​×[H+]old​ Taking the negative logarithm to find the new pH: pHnew=−log⁡(1100×[𝐻+]old)pHnew​=−log(1001​×[H+]old​) =−log⁡(1100)−log⁡([𝐻+]old)=−log(1001​)−log([H+]old​) =−log⁡(0.01)−log⁡([𝐻+]old)=−log(0.01)−log([H+]old​) =−(−2)−log⁡([𝐻+]old)=−(−2)−log([H+]old​) =2−pHold=2−pHold​ Given that the old pH (pHoldpHold​) is 5.9: pHnew=2−5.9=−3.9pHnew​=2−5.9=−3.9 Since the pH is now negative, the solution will be more acidic. Therefore, the solution will be more acidic.