How do know if a redox equation is acidic or basic
Answers
Answer:
Balancing redox reactions first requires splitting the equation into the two half-reactions of reduction and oxidation. All atoms except oxygen and hydrogen should be balanced first. In acidic conditions, the oxygen atoms should be balanced with water, while hydrogen atoms should be balanced with H+.
Answer:
Redox is an oxidation - reduction reaction, where both of them are taking place. From reaction mechanism, you can tell whether “the reaction is taking place in a acidic or basic medium” ( if H+ is present during balancing the reaction then it's acidic medium, and if OH- is present then it's basic medium)
balancing them
The first step in balancing any redox reaction is determining whether or not it is even an oxidation-reduction reaction. This requires that one and typically more species changing oxidation states during the reaction. To maintain charge neutrality in the sample, the redox reaction will entail both a reduction component and an oxidation components. These are often separated into independent two hypothetical half-reactions to aid in understanding the reaction. This requires identifying which element is oxidized and which element is reduced. For example, consider this reaction:
Cu(s)+2Ag+(aq)→Cu2+(aq)+2Ag(s)
The first step in determining whether the reaction is a redox reaction is to split the equation into two hypothetical half-reactions. Let's start with the half-reaction involving the copper atoms:
Cu(s)→Cu2+(aq)
The oxidation state of copper on the left side is 0 because it is an element on its own. The oxidation state of copper on the right hand side of the equation is +2. The copper in this half-reaction is oxidized as the oxidation states increases from 0 in Cu to +2 in Cu2+ . Now consider the silver atoms
2Ag+(aq)→2Ag(s)
In this half-reaction, the oxidation state of silver on the left side is a +1. The oxidation state of silver on the right is 0 because it is an pure element. Because the oxidation state of silver decreases from +1 to 0, this is the reduction half-reaction.
Consequently, this reaction is a redox reaction as both reduction and oxidation half-reactions occur (via the transfer of electrons, that are not explicitly shown in equations 2). Once confirmed, it often necessary to balance the reaction (the reaction in equation 1 is balanced already though), which can be accomplished in two ways because the reaction could take place in neutral, acidic or basic conditions
balancing solutions
Balancing redox reactions is slightly more complex than balancing standard reactions, but still follows a relatively simple set of rules. One major difference is the necessity to know the half-reactions of the involved reactants; a half-reaction table is very useful for this. Half-reactions are often useful in that two half reactions can be added to get a total net equation. Although the half-reactions must be known to complete a redox reaction, it is often possible to figure them out without having to use a half-reaction table. This is demonstrated in the acidic and basic solution examples. Besides the general rules for neutral conditions, additional rules must be applied for aqueous reactions in acidic or basic conditions.
One method used to balance redox reactions is called the Half-Equation Method. In this method, the equation is separated into two half-equations; one for oxidation and one for reduction.
Half-Equation Method to Balance redox Reactions in Acidic Aqueous Solutions
Each reaction is balanced by adjusting coefficients and adding H2O , H+ , and e− in this order:
Balance elements in the equation other than O and H .
Balance the oxygen atoms by adding the appropriate number of water ( H2O ) molecules to the opposite side of the equation.
Balance the hydrogen atoms (including those added in step 2 to balance the oxygen atom) by adding H+ ions to the opposite side of the equation.
Add up the charges on each side. Make them equal by adding enough electrons ( e− ) to the more positive side. (Rule of thumb: e− and H+ are almost always on the same side.)
The e− on each side must be made equal; if they are not equal, they must be multiplied by appropriate integers (the lowest common multiple) to be made the same.
The half-equations are added together, canceling out the electrons to form one balanced equation. Common terms should also be canceled out.
The equation can now be checked to make sure that it is balanced.
Half-Equation Method to Balance redox Reactions in Basic Aqueous Solutions
If the reaction is being balanced in a basic solution, the above steps are modified with the the addition of one step between #3 and #4:
3b Add the appropriate number of OH− to neutralize all H+ and to convert into water molecules.
The equation can now be checked to make sure that it is balanced.