Why reversed Carnot cycle is not possible?
In real engines, the heat transfers at a sudden change in temperature whereas in a Carnot engine, the temperature remains constant. In our day to day lives, reversible processes can’t be carried out and there is no such engine with 100 % efficiency. Thus, the Carnot cycle is practically not possible.
What are the limitations of reversed Carnot cycle?
Reversed Carnot refrigeration cycle with liquefaction and vaporization of the refrigerant. There are two major drawbacks to the reversed Carnot cycle with phase-change refrigerant: 1. The adiabatic compression between Tlow and Thigh occurs in the liquid–vapor region, which is why it is called wet compression.
What happens when a Carnot cycle is run in reverse?
Reversing the Carnot cycle does reverse the directions of heat and work interactions. A refrigerator or heat pump that operates on the reversed Carnot cycle is called a Carnot refrigerator or a Carnot heat pump.
Why is the Carnot cycle impractical as a device for generating power?
Fig. 2-2: Carnot vapor cycle. … Carnot cycles are not encountered in reality since achieving isothermal heat transfer is very difficult (needs very large heat exchangers and long time). Also process 3-4 requires a pump or compressor that can handle two phase mixture (liquid and vapor) which is impractical.
How is the cop of reversed Carnot cycle improved?
C.O.P. of the reversed Carnot cycle may be improved by decreasing higher temperature i.e. temperature of hot body T2. Increasing lower temperature i.e. temperature of cold body T1 also improves C.O.P. Although this cycle gives maximum C.O.P.
Which of the following process is reversible?
Isothermal compression is reversible, for example, Carnot cycle, heat engine.
Which processes are reversible?
Here, we have listed a few examples of Reversible Process:
- extension of springs.
- slow adiabatic compression or expansion of gases.
- electrolysis (with no resistance in the electrolyte)
- the frictionless motion of solids.
- slow isothermal compression or expansion of gases.
What is a Carnot cycle What is its purpose?
Carnot cycle, in heat engines, ideal cyclical sequence of changes of pressures and temperatures of a fluid, such as a gas used in an engine, conceived early in the 19th century by the French engineer Sadi Carnot. It is used as a standard of performance of all heat engines operating between a high and a low temperature.
Which of the following EAS is reversible?
Sulfonation of benzene is a reversible reaction. Sulfur trioxide readily reacts with water to produce sulfuric acid and heat.
Which of the following process is an irreversible one?
The examples of irreversible processes are Motion with friction, free expansion, Expansion/ compression with finite pressure difference, Energy transfer as heat with finite, mixing of matter at different states, Mixing of non-identical gases, transfer of electricity through resistor.
Which of the following process is not reversible?
Since the entropy of mixing is positive we can say the mixing process or solution formation process is an irreversible process.
Why is sulfonation reversible?
Sulfonation of benzene is a reversible reaction. Sulfur trioxide readily reacts with water to produce sulfuric acid and heat. Therefore, by adding heat to benzenesulfonic acid in diluted aqueous sulfuric acid the reaction is reversed.
What is true about reversible reaction?
A reversible reaction is a reaction in which the conversion of reactants to products and the conversion of products to reactants occur simultaneously. … The two reactions can be combined into one equation by the use of a double arrow. The double arrow is the indication that the reaction is reversible.
Which statement is true about a reversible reaction?
A reversible chemical reaction can occur in both directions, in that reactants can turn into products and products can turn into reactants.
Is Sulphonation reversible?
Unlike the other electrophilic aromatic substitution reactions, sulfonation is reversible. Removal of water from the system favours the formation of the sulfonation product. … Sulfonation with fuming sulfuric acid strongly favours formation of the product the sulfonic acid.
What is the role of FeBr3 in the bromination of toluene?
What is the Bromination of Benzene mechanism? … What is the function of the FeBr3 complex in the bromination of benzene? It functions as a lewis acid (accepts electrons from Br2) It is regenerated in the end and is thus a catalyst. What other catalyst is similar to FeBr3 and can serve a similar purpose?
What is the role of HNO3 in nitration of benzene?
HNO3 acts as a base in the nitrating mixture and provides the electrophile NO2+ .
What is the role of concentrated h2so4 in the nitration test?
In the protonation of nitric acid by sulfuric acid, the source of the nitronium ion induces the removal of a water molecule and the creation of a nitronium ion. By cooling an amount of condensed sulfuric acid, typically in an ice bath, nitrating mixtures are prepared. …
What is Sulphonation process?
The air/SO3 sulfonation process is a direct process in which SO3 gas is diluted with very dry air and reacted directly with the organic feedstock. The source of the SO3 gas may be either liquid SO3 or SO3 produced by burning sulfur.
What is the electrophile in Sulphonation of benzene?
The electrophile involved in the sulphonation of benzene is SO3.
Why Ortho product is major in nitration of toluene?
Ortho nitrotoluene is a major product while para nitrotoluene is a minor product . Reasons: In case of reactivity: Ortho product is more reactive comparing with para product because electron density is more enriched at ortho position compared to the para position.
Why nitration is usually carried out at lower temperature?
Methylbenzene reacts rather faster than benzene – in nitration, the reaction is about 25 times faster. That means that you would use a lower temperature to prevent more than one nitro group being substituted – in this case, 30°C rather than 50°C.
What happens when toluene reacts with conc nitric acid?
(i) toluene reacts with the nitrating mixture to form a mixture of para nitro and ortho nitro toluene .