Ch.15 - Acid and Base EquilibriumWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: Which is a stronger base, S2 -  or Se2-?

Solution: Which is a stronger base, S2 -  or Se2-?

Problem

Which is a stronger base, S2 -  or Se2-?

Solution

We are asked which is the stronger base, S2- or Se2-.

The conjugate base of an acid is the species formed after an acid donates a proton. The general reaction is as follows:

                                  Acid + Base  Conjugate Base + Conjugate Acid


The strengths of conjugate bases of binary acids are based on the electronegativity of the nonmetal in the binary acid. 

conjugate base is considered stronger when its binary acid is weaker. 


Given:

S2-              Se2-            

The binary acids counterparts are:

   H2S               H2Se

The reaction forming the conjugate bases are:

  H2S +H2 H3O+ + S2-

  H2Se + H2 H3O+ + Se2-


We’ll rank their strength based on the electronegativity of the nonmetal in each binary acid.

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