Quel volume d'une solution de soude 0,1 M faut-il ajouter à 1 litre d'une solution d'acide chlor

Quel volume d'une solution de soude 0,1 M faut-il ajouter à...

Key Concepts

Acid-Base Neutralization Reaction

This concept involves the reaction between an acid and a base, where H+ ions from the acid combine with OH- ions from the base to form water. Understanding this reaction is crucial because it allows one to determine how the addition of a base affects the concentration of unreacted acid, which directly influences the pH of the solution.

pH and Hydrogen Ion Concentration

pH is a measure of the acidity of a solution that is defined as the negative logarithm (base 10) of the hydrogen ion concentration. This concept is fundamental for understanding how changes in [H+]—resulting from neutralization reactions or dilution—alter the solution's acidity, and it is essential for solving problems that require setting a specific pH.

Molarity and Volume Relationships

Molarity represents the concentration of a solution in terms of moles of solute per liter, and it is used alongside the volume of a solution to determine the number of moles of substance present. This relationship is key in titration and neutralization problems where the number of moles of acid or base must be calculated to understand the extent of the reaction.

Titration Calculations

Titration involves gradually adding one solution to another until the reaction reaches a target point, such as a specified pH or complete neutralization. The calculations stem from determining how many moles of titrant (acid or base) are added to achieve the desired concentration of hydrogen ions, and this process is central to analyzing and controlling the reaction dynamics during titration.

Transcript

00:01 This question asks to address the concept of acid -based chemistry and how ph and p -o -h play into that.

00:07 The question basically asks, how does the concentration of hydroxide or hydronium ion change when the ph of the solution gets adjusted from a 3 .15 to a 3 .65.

00:20 So the first thing we need to recognize is that when we increase ph, that means we have a less acidic solution or we'd have more hydroxide ion.

00:30 Present in a solution with a higher ph.

00:34 So to adjust a solution from a lower ph to a higher, we need to add hydroxide ion.

00:40 So that's the first thing we need to recognize.

00:43 The next is how much or how do we quantify how much the hydroxide ion concentration changes.

00:51 And probably the best way to do this is to use the relationship between ph and p .o .h.

00:57 That together in an aqueous solution, they equal 14.

01:01 And let's just look at how the poh changes when we change that value first for a ph of 3 .15 and do it again for a ph of 3 .65 and find the two different pow values at those two different values of ph.

01:24 So plugging in the two different values of ph into the known equation, we find that the poh initially at the ph of 3 .15 is 10 .85.

01:35 And as we adjust the ph to a higher value 3 .65, that p .o .h value falls down to 10 .35.

01:43 Remember on the p .o .h scale, the lower the number, the more basic the solution is.

01:49 Just like on the ph scale, the lower the number, the more acidic solution is...

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