In acid-base chemistry, the leveling effect refers to the limitation imposed by the solvent on the strength of acids and bases in solution. When a base stronger than the solvent's conjugate base is used, it deprotonates the solvent until the base is entirely consumed, making it ineffective against weaker acids. Conversely, an acid stronger than the solvent's conjugate acid protonates the solvent until the acid is depleted, rendering it ineffective against weaker bases. Essentially, the solvent neutralizes stronger acids and bases, preventing them from reacting as intended with other compounds.

For example, in water (an aqueous solution), a strong base like the amide ion deprotonates water, predominantly forming hydroxide ions and leaving few amide ions. This prevents the amide ions from effectively deprotonating compounds like acetylene, which have a higher pKa than water. However, if a more basic solvent like ammonia is used, the amide ions can successfully deprotonate acetylene, facilitating the desired reaction.

In summary, the solvent's acidity limits the effectiveness of strong bases, and its basicity limits the effectiveness of strong acids. The chosen solvent must, therefore facilitate the acid-base reaction without undergoing a significant reaction itself.

タグ
Leveling EffectAcid base ChemistrySolventConjugate BaseConjugate AcidNeutralizationProtonationDeprotonationWaterAmmoniaHydroxide IonsAmide IonsAcetylene

章から 3:

article

Now Playing

3.14 : Leveling Effect

酸塩基滴定

560 閲覧数

article

3.1 : 酸-塩基滴定:概要

酸塩基滴定

6.4K 閲覧数

article

3.2 : 強塩基による強酸の滴定

酸塩基滴定

4.5K 閲覧数

article

3.3 : 強塩基による弱酸の滴定

酸塩基滴定

1.6K 閲覧数

article

3.4 : 強酸による弱塩基の滴定

酸塩基滴定

4.0K 閲覧数

article

3.5 : 弱塩基を有する弱酸の滴定

酸塩基滴定

2.0K 閲覧数

article

3.6 : 酸/塩基滴定中の溶液組成

酸塩基滴定

383 閲覧数

article

3.7 : 酸の混合物

酸塩基滴定

413 閲覧数

article

3.8 : 非水系溶媒中での滴定

酸塩基滴定

504 閲覧数

article

3.9 : 強酸によるポリプロティック塩基の滴定

酸塩基滴定

434 閲覧数

article

3.10 : 強塩基によるポリプロトン酸の滴定

酸塩基滴定

1.5K 閲覧数

article

3.11 : pHの関数としてのポリプロトン酸溶液の組成

酸塩基滴定

339 閲覧数

article

3.12 : バッファ:概要

酸塩基滴定

3.5K 閲覧数

article

3.13 : バッファ: バッファ容量

酸塩基滴定

867 閲覧数

JoVE Logo

個人情報保護方針

利用規約

一般データ保護規則

研究

教育

JoVEについて

Copyright © 2023 MyJoVE Corporation. All rights reserved