How Temperature Affects The Rate Of Reaction Between Sodium Thiosulphate And Hydrochloric Acid Experiment And Explanation
Temperature Effects on Reactions
Our world is full of things which we don’t know off, things which are taking place right in front of our eyes and still we are not aware of them. One of the most common occurrence that we can’t see from our eyes are chemical reactions. In some cases, they might be too slow, while on the other hand, some are too fast, but most of them are unrecognisable to us in daily lives. From putting mentos in your coke bottle to the engine of a car, we have reactions taking place all around us. Today we are going to discuss how temperature could affect a given reaction, and in this case, we react with Sodium thiosulphate and Hydrochloric acid. Not only does the temperature have some severe effect on this reaction, but other reactions get manipulated by the temperature in big industries to get the most from the reaction.
Properties of Hydrochloric Acid
Before we dive deep into the reaction of these two compounds, it is fair to have some background about them to make it easier for us to understand how the temperature affects each of them individually.
Hydrogen oxide being a liquid solution of hydrochloric acid is one of the most potent mineral acids. As a result, industries use it extensively in their production. We represent Hydrochloric acid as HCl when writing its chemical formula., and it is the mixture of hydrogen and chloride present in water.
The acid is clear and doesn’t have any colour, but it does have a high pungent odour which can smell even from a distance if its bottle gets opened. The boiling hydrochloric acid rate and the melting point varies depending on its concentration in water.
The fuming hydrochloric acid forms when the hydrogen and chlorine hold 38% of the total concentration with the water. The HCl which is used in industries has a concentration of 30%-35%. On the other hand, if we look at the commercial side of HCl, we get muriatic acid which is in between 20% to 32% of concentration.
HCl can release only one hydrogen positive ion. Thus, it comes in the list of one of the strong acids and also called monoprotic acid. It gives us hydronium and chloride ions when it gets to react with water. If you want to dissolve a strong metal, you can take the help of Hydrochloric acid as it can from oxidised metal chlorides and hydrogen gas. Any biological sample which you break down HCl can help you digest it in no time. You can see its use in photographic, textile, and rubber industries.
Properties of Thiosulphate
Thiosulphate is said to be an important inorganic salt that provides several medical uses to doctors. In other words, we can call it ‘hyp’; it's the acronym of sodium hyposulfite. The chemical formula of this compound is Na2S2O3. It is also present in the state of pentahydrate salt. Thiosulphate is an ionic compound that has two sodium cations present along with thiosulfate anion. In this compound, we have sulfur atoms at the centre which is bonded with three oxygen atoms and with one sulfur atom. All of these are connected via single and double bonds with the characteristics of resonance.
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Furthermore, the compound is highly soluble in water and has a physical property as a crystalline solid which is odourless. Under normal temperature and conditions, it remains solid, but when some extra heat is applied, it dissolves to give sodium sulfate and sodium polysulfide.
Effects of Temperature on Rate of Reaction
From this reaction, we get precipitate of sulfur forms. The time which is taken to produce a certain amount of precipitate of sulfur is used to show us the rate of reaction for lab report discussion. One thing you need to keep in mind is to wear glasses and keep your face away from the test tube while the reaction is taking place. Because of sulfur dioxide as a by-product of this reaction which is a toxic gas, it can cause you breathing issues if you inhale it.
The rate of reaction of the two compounds is directly proportional to the increase in temperature. When we increase the temperature, the molecules of a compound start to vibrate at a much faster rate resulting in a collision with particles of another compound. As a result, their collision leads to the reaction of the two compounds, and more the collision, the shorter will be the time in which the reaction gets completed.
But hold on, that’s not it when we increase the temperature the activation energy also reaches to its potential. Meaning the particles have now enough energy to start the reaction. The minimum energy which is required to start up a reaction between two compounds or chemicals is called activation energy.
FAQs on Effect Of Temperature On The Rate Of Reaction Between Sodium Thiosulphate And Hydrochloric Acid
1. What is the reaction between sodium thiosulphate and hydrochloric acid?
The reaction between sodium thiosulphate and hydrochloric acid produces sulphur, sulphur dioxide, water, and sodium chloride. The balanced chemical equation is:
Na2S2O3(aq) + 2HCl(aq) → 2NaCl(aq) + SO2(g) + S(s) + H2O(l)
Key observations in this rate of reaction experiment:
- A yellow precipitate of sulphur forms.
- The solution becomes cloudy.
- Sulphur dioxide gas with a pungent smell is released.
2. How does temperature affect the rate of reaction between sodium thiosulphate and hydrochloric acid?
Increasing temperature increases the rate of reaction between sodium thiosulphate and hydrochloric acid. As temperature rises:
- Particles gain more kinetic energy.
- Collision frequency increases.
- A greater proportion of particles have energy ≥ activation energy.
3. Why does the solution turn cloudy in the sodium thiosulphate and hydrochloric acid reaction?
The solution turns cloudy because solid sulphur (S) is formed as a precipitate during the reaction. In the reaction:
Na2S2O3(aq) + 2HCl(aq) → 2NaCl(aq) + SO2(g) + S(s) + H2O(l)
The sulphur produced is insoluble in water and appears as a fine yellow solid, causing turbidity. This cloudiness is used to measure reaction rate by timing how long it takes to obscure a marked cross.
4. What is the aim of the sodium thiosulphate and hydrochloric acid rate experiment?
The aim of this experiment is to investigate the effect of temperature on the rate of reaction between sodium thiosulphate and hydrochloric acid. Specifically, it measures:
- How increasing temperature changes reaction speed.
- The time taken for sulphur precipitate to form.
- The relationship between temperature and collision frequency.
5. How do you measure the rate of reaction in the sodium thiosulphate and hydrochloric acid experiment?
The rate of reaction is measured by timing how long it takes for a cross beneath the flask to disappear due to sulphur formation. The steps are:
- Place a conical flask over a paper with a black cross.
- Add hydrochloric acid to sodium thiosulphate solution.
- Start a stopwatch immediately.
- Stop timing when the cross is no longer visible.
6. What is the role of activation energy in this reaction?
The activation energy is the minimum energy required for sodium thiosulphate and hydrochloric acid particles to react successfully. When temperature increases:
- More particles have energy equal to or greater than activation energy.
- More effective collisions occur.
- The reaction rate increases.
7. What type of reaction is sodium thiosulphate with hydrochloric acid?
The reaction between sodium thiosulphate and hydrochloric acid is a precipitation and decomposition reaction. In this process:
- Thiosulphate ions break down in acidic conditions.
- Solid sulphur precipitates out.
- Sulphur dioxide gas is released.
8. Why is sodium thiosulphate used to study the effect of temperature on reaction rate?
Sodium thiosulphate is used because it produces a visible sulphur precipitate that makes the reaction rate easy to measure. Its advantages include:
- Clear visual change (cloudiness).
- Moderate reaction speed suitable for timing.
- Safe and easy handling in school laboratories.
9. What are the variables in the sodium thiosulphate and hydrochloric acid temperature experiment?
The key variables in this rate of reaction experiment are:
- Independent variable: Temperature of the reaction mixture.
- Dependent variable: Time taken for the cross to disappear (rate of reaction).
- Controlled variables: Concentration and volume of reactants, total volume, and same visual method of observation.
10. What safety precautions are needed for the sodium thiosulphate and hydrochloric acid reaction?
Safety precautions are required because hydrochloric acid is corrosive and sulphur dioxide gas is harmful. Important precautions include:
- Wear safety goggles and a lab coat.
- Handle HCl(aq) carefully to avoid skin contact.
- Perform the experiment in a well-ventilated area or fume hood.
- Avoid inhaling SO2(g).
