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A double replacement reaction will occur if a formation of a precipitate , gas or water takes place. Select two compounds above and this calculator will predict whether or not the reaction will occur in water. This is simply based on the solubility chart of inorganic compounds. It must be noted that the results are not 100% physically correct ...
- Overview
- What is a double replacement reaction?
- Precipitation and neutralization reactions
- Example: predicting and balancing a double replacement reaction
- Summary
- Try it!
Definition and examples of double replacement reactions. Predicting and balancing neutralization and precipitation reactions.
Double replacement reactions—also called double displacement, exchange, or metathesis reactions—occur when parts of two ionic compounds are exchanged, making two new compounds. The overall pattern of a double replacement reaction looks like this:
A+B−+C+D−→A+D−+C+B−
You can think of the reaction as swapping the cations or the anions, but not swapping both since you would end up with the same substances you started with. The solvent for a double replacement reaction is usually water, and the reactants and products are usually ionic compounds—but they can also be acids or bases.
Here is an example of a double replacement reaction:
BaCl2(aq)+Na2SO4(aq)→BaSO4(s)+2NaCl(aq)
In this example, the cations are Ba2+ and Na+ , and the anions are Cl− and SO42− . If we swap the anions, or cations, we get as our products BaSO4 and NaCl .
Identifying double replacement reactions is usually fairly straightforward once you can recognize the pattern. Predicting whether the reaction will occur can be trickier; it helps to be able to recognize some common types of double replacement reactions. In this article we will be discussing precipitation reactions and neutralization reactions.
A precipitation reaction is when two aqueous ionic compounds form a new ionic compound that is not soluble in water. One example is the reaction between lead (II) nitrate and potassium iodide. Both compounds are white solids that can be dissolved in water to make clear, colorless solutions. When you combine the two clear solutions, you get the following reaction:
Pb(NO3)2(aq)+2KI(aq)→2KNO3(aq)+PbI2(s)
We made a beautiful golden solid from two clear solutions! In real life, your reaction flask might look something like the picture below.
The insoluble product compound is called the precipitate. The solvent and soluble components of the reaction are called the supernatant or supernate. We can use solubility rules to predict whether a precipitation reaction will take place. The formation of a solid precipitate is the driving force that makes the reaction proceed in the forward direction.
[What do you mean by a driving force?]
Let’s take a look at an example where we don't know the products:
H2SO4(aq)+Ba(OH)2(aq)→
First, we can identify the cations and anions that will get swapped. The cations are H+ and Ba2+ , and the anions are SO42− and OH− . Swapping anions gives the products H2O and BaSO4 :
H2SO4(aq)+Ba(OH)2(aq)→H2O+BaSO4
We can see that our double replacement reaction is also a neutralization reaction since we are reacting sulfuric acid, a strong acid, with barium hydroxide, a strong base. What is the state of the product barium sulfate? If we check our solubility rules, we see that barium sulfate is insoluble and should precipitate out of solution. That means our reaction is a precipitation reaction, too! We can also include that information in our equation by adding the symbol (s) after the BaSO4 .
We aren’t quite done yet, though. Our reaction is not balanced since we have unequal numbers of hydrogens and oxygens on both sides of the arrow. We can fix this by multiplying H2O by 2 to give our final, balanced molecular equation:
Double replacement reactions have two ionic compounds that are exchanging anions or cations. Precipitation reactions and neutralization reactions are two common types of double replacement reactions. Precipitation reactions produce an insoluble product from two aqueous reactants, and you can identify a precipitation reaction using solubility rules. Neutralization reactions occur when the reactants are an acid and a base, and neutralization reactions are usually favorable as long as the reaction involves a strong acid and/or a strong base.
[Attributions and references]
Problem 1
For the following reactants, what are the products of the double displacement reaction? FeCl3(aq)+Ba(OH)2(aq)→ Choose 1 answer: Choose 1 answer: •(Choice A) no reaction •(Choice B) Fe(OH)2(s)+BaCl(aq) •(Choice C) FeBa(s)+HOCl(aq) •(Choice D) Fe(OH)3(s)+BaCl2(aq) [Hint 1] [Hint 2]
Problem 2
What type of reaction is the above reaction? Choose all answers that apply: Choose all answers that apply: •(Choice A) Oxidation-reduction reaction •(Choice B) Double replacement reaction •(Choice C) Neutralization reaction •(Choice D) Precipitation reaction [Hint 1] [Hint 2]
Calculate chemical reactions step-by-step with this free online tool. Enter the reactants and products, and get the balanced equation, the coefficients, and the types of reactions.
During double replacement, the cations and anions of two different compounds switch places. Written using generic symbols, it is: AB + XY ---> AY + XB. A and X are the cations (postively-charged ions) in this example, with B and Y being the anions (negatively-charged ions).
Aug 19, 2020 · Double-Replacement Reactions . A double-replacement reaction is a reaction in which the positive and negative ions of two ionic compounds exchange places to form two new compounds. The general form of a double-replacement (also called double-displacement) reaction is: \[\ce{AB} + \ce{CD} \rightarrow \ce{AD} + \ce{CB}\nonumber \]
Chemical Reaction Calculator. Added Feb 13, 2014 by Jose Ramon in Chemistry. Chemistry equatinos. Send feedback | Visit Wolfram|Alpha. Get the free "Chemical Reaction Calculator" widget for your website, blog, Wordpress, Blogger, or iGoogle.
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Nov 23, 2020 · An example of a double replacement reaction is the reaction between silver nitrate and sodium chloride in water. Both silver nitrate and sodium chloride are ionic compounds. Both reactants dissolve into their ions in aqueous solution. The silver ion picks up the sodium’s chloride ion to form silver chloride, while the sodium ion picks up the ...
