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Question
Which among the following are physical or chemical change?
Curding of milk
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Solution
Chemical
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RELATED QUESTIONS
Define ‘redox reaction’. Give one example.
When SO2 gas is passed through saturated solution of H2S, the following reaction occurs:
SO2 + 2H2S → 2H2O + 3S
In this reaction, which substance is oxidised and which one is reduced?
Define oxidation in terms of gain or loss of hydrogen with one example.
Explain the following in term of gain or loss of oxygen with two examples.
Reduction
State whether the following conversion is oxidation or reduction:
Cu2+ + 2 e-→ Cu
In the following reaction: A+ + B → A + B+. Write half-reactions for this reaction and name:
- oxidizing agent
- substance oxidized
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Which of the following statements about hydrogen is incorrect?
Name:
a substance that oxidizes concentrated HCl to chlorine.
With reference to oxidation & reduction reaction – complete the statement given by filling in the blanks with only the words (a) Addition (b) Removal.
‘Oxidation is a chemical reaction involving ____ of oxygen to a substance or ____ of hydrogen from a substance. Reduction on the otherhand involves ____ of hydrogen to a substance or ____ of oxygen from a substance.
Give two test for an oxidising agent.
Select the correct answer from the symbol in the bracket.
The element, which like hydrogen is a strong reducing agent.
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- C in CO2
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The process of reduction involves ____________.
\[\ce{MnO2 + 4HCl -> + 2H2O + Cl2}\]
Identify the substance oxidized in the above equation.
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`"CuSO"_4 + "Zn" -> "Cu" + "ZnSO"_4`
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Grapes hanging on the plant do not ferment but after being plucked from the plant can be fermented. Under what conditions do these grapes ferment? Is it a chemical or a physical change?
During the reaction of some metals with dilute hydrochloric acid, following observations are made.
Some bubbles of a gas are seen when lead (Pb) is reacted with the acid.
Explain this observation giving suitable reason.
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\[\ce{MnO_2 + 4HCl->MnCl_2 +2H_2O + Cl_2}\]
