I believe this is a double replacement. As you can see none of the chemical symbols are missing, there just "replaced".
Petrol is a conductor of electricity, because it conducts rather than insulates.
Answer:
(A) first order reaction
Explanation:
A first order reaction is a type of reaction in which the rate of the reaction depends only on the concentration on one of the reactants. Since A is the only reactant we have, it is right to deduce that this reaction is a first order reaction.
Note: while the order of this reaction is 1, its molecularity is 2. The molecularity of a reaction is the number of moles of reactants that is actually reacting.
(B) is wrong
This is because a zero order reaction is one in which the rate of reaction is not influenced by the concentrations of the reactants and hence remains constant irrespective. Since we were not furnished with this idea in the question, it is only right that we reject this answer.
(C) is wrong.
C is outrightly wrong as we have only one reactant.
(D) is wrong
We have only one reactant.
Explanation:
- Evaporation is defined as a process in which liquid state of water is changing into vapor state.
So, we need to break the bonds of liquid substance in order to convert it into vapor state. And, energy is absorbed for breaking of bonds which means that evaporation is an endothermic process.
Hence, the statement evaporation of water is an exothermic process is false.
- When a hydrocarbon reacts with oxygen and leads to the formation of carbon dioxide and water then this type of reaction is known as combustion reaction.
A combustion reaction will always release heat energy. Hence, combustion reaction is exothermic in nature.
- When energy is transferred as heat from the surroundings to the system then it means energy is being absorbed by the system. And, absorption of heat is an endothermic process for which
is positive.
- Whereas when energy is transferred from system to the surrounding then it means energy is released by the system which is an exothermic process.
Hence, for an exothermic process value of
is negative.
Thus, we can conclude that statements which are true are as follows.
- A combustion reaction is exothermic.
- When energy is transferred as heat from the system to the surroundings,
is negative.
- For an endothermic reaction Deta H is positive.