Advertisements
Advertisements
Question
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?
Solution
Grapes hanging on the plants are living in nature. Their immune system does not allow any fermentation.
However, when these are plucked, they are no longer living. They undergo fermentation under aerobic conditions (in the absence of air or oxygen). The other factors which favour fermentation are enzyme and temperature between 25°C to 30°C. The fermentation is a chemical change.
APPEARS IN
RELATED QUESTIONS
The process of respiration is:
(a) an oxidation reaction which is endothermic
(b) a reduction reaction which is exothermic
(c) a combination reaction which is endothermic
(d) an oxidation reaction which is exothermic
Identify from the following reaction the reactants that undergo oxidation and reduction.
2Ag2O → 4 Ag + O2 ↑
State, giving reason, whether the substances printed in bold letters have been oxidized or reduced.
Cl2 + H2S → 2HCl + S
State whether the following conversion is oxidation or reduction:
PbO2 + SO2→ PbSO4
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.
A silver article generally turns black when kept in the open for a few days. The article when rubbed with toothpaste again starts shining.
- Why do silver articles turn black when kept in the open for a few days? Name the phenomenon involved.
- Name the black substance formed and give its chemical formula.
Write a short note on oxidizing and reducing agents.
Oxidizing agents are otherwise called ______.
Choose the odd one out and write the reason:
Find the oxidation number of the element in the following compound.
N in NH3
