CaCl2 + NaOH = Ca(OH)2 + NaCl Reaction and Characteristics
Calcium chloride (CaCl2) reacts with aqueous NaOH to produce calcium hydroxide ( Ca(OH)2 ) and NaCl. Ca(OH)2 is a white precipitate. You can see a white precipitate is deposited at the bottom of the solution when two solutions are mixed. But, if when concentration of ions (calcium and hydroxyl) are too low, Ca(OH)2 can be dissolved in water. We will discuss about these characteristics of the CaCl2 + NaOH reaction in this tutorial.
Aqueous calcium chloride and aqueous sodium hydroxide
Calcium chloride is a soluble inorganic compound in water and form a colorless solution.
Sodium hydroxide is a strong alkaline colorless solution and readily gives hydroxyl ions (OH-).
What are the products when aqueous CaCl2 reacts with aqueous NaOH
When we add aqueous NaOH solution to aqueous CaCl2 solution, a white precipitate is formed. This precipitate is calcium hydroxide (Ca(OH)2). However, if ion concentrations of calcium and hydroxyl ions are very low, calcium hydroxide can be dissolved in water and give colorless solution. Therefore, having enough calcium and hydroxyl ion concentration is importnat for precipitating.
CaCl2 + NaOH = Ca(OH)2 + NaCl
Above mentioned reaction is not a balanced chemical reaction. So, we need to balance this reaction and we will do it next section.
How to balance CaCl2 and NaOH reaction?
This reaction is a not a redox reaction. Therefore by observing number of atoms in right side and left side of the equation, we can balance the reaction in few seconds. This method is a trial and error method. But it is easy to balance this reaction. If you are a beginner of chemistry, this a good reaction to start learning of balancing chemical equations.
Balanced reaction and stoichiometry of CaCl2 and NaOH
CaCl2 + 2NaOH = Ca(OH) + 2NaCl
According to the stoichiometry of the balanced equation, 1 mol of CaCl2 reacts with 2 mol of NaOH and produce 1 mol of Ca(OH)2 and 2 mol of NaCl.
Balanced reaction of CaCl2 and NaOH with physical states
CaCl2(aq) + NaOH(aq) = Ca(OH)2(s) + 2NaCl(aq)
CaCl2 is very much soluble in water. Therefore, it exists as an aqueous solution and NaOH also exists as a solution. But, solubility of Ca(OH)2 is low in water and may depend on the ion concentrations of Ca2+ ions OH-. Hence if concentration of ions are high it (Ca(OH)2(s)) deposits as a white precipitate at the bottom of the reaction. NaCl is very much soluble in water and exists as an aqueous solution.
Questions asked by students
Ask your question and find the answer free.
What are the physical states of CaCl2 and NaOH reaction?
CaCl2 is soluble in water. Therefore it exists as an aqueous state. NaOH is also soluble in water and exists as an aqueous state. Ca(OH)2 is not soluble in water and exist as solid state. Other product, NaCl is highly soluble in water and exists as an aqueous state.
From this NaOH and CaCl2 reaction, can we prove existing of chloride ion?
I think, you want to test chloride ion. There are several ways to prove existing of chloride ion in aqueous solutions. But, with NaOH, you cannot see a exceptional reaction or change happening due to chloride ion. Instead of calcium chloride, assume that there was calcium nitrate. Both calcium chloride and calcium nitrate give white colour calcium hydroxide white precipitate with NaOH whether calcium is combined with chloride ion or nitrte ion.
Is calcium chloride a precipitate?
Calcium chloride is a colourless solution.
How pH value is changed when naoh is added to CaCl2 solution?
When NaOH is added drop by drop to CaCl2 solution, free hydroxyl ions exists in the solution. That means solution become basic and pH value increaes.
What are the other compounds can be used instead of CaCl2 to form Ca(OH)2 precipitate?
Ca(NO3)2 can be used. Ca(SO4)2 cannot be used because solubility of Ca(SO4)2 is low in water.
How color of the solution is changed CaCl2 + NaOH reaction
Both CaCl2 and NaOH are colorless solution. But, when they are mixed, a white precipitate is given. When precipitate is separated from the solution, a colorless solution can be seen.
What is the color of precipitate formed by CaCl2 + NaOH
Ca(OH)2 is a white color precipitate
Question of forming Ca(OH)2 precipitating
In an experiment, you are going to see whether Ca(OH)2 is precipitated by mixing 50 cm3 of 0.1 M NaOH and 50 cm3 of 0.1 M CaCl2 solutions. Solubility of Ca(OH)2 is 1.73 g/ l
First, we should want to find how much amount (mole) of Ca(OH)2 will be formed in this reaction.
- Amount of NaOH = 0.005 mol
- Amount of CaCl2 = 0.005 mol
- Formed Ca(OH)2 amount= 0.0025 mol
- Formed Ca(OH)2 mass = 0.005 mol * 74 g/mol
- Formed Ca(OH)2 mass = 0.185 g
According to the solubility data, soluble Ca(OH)2 mass in 100 ml = 0.173 g
Formed Ca(OH)2 mass is greater than maximum soluble Ca(OH)2 mass. Therefore, a precipitate should be formed.will be formed in this reaction.
How to prepare Ca(OH)2? not from this reaction
Use calcium nitrate solution. Add aqueous sodium hydroxide solution to aquoeus calcium nitrate solution. This reaction will give Ca(OH)2 precipitate.