Advertisements
Advertisements
प्रश्न
Which among the following are physical or chemical change?
Evaporation of petrol
Advertisements
उत्तर
Physical
APPEARS IN
संबंधित प्रश्न
What are anti-oxidants? Why are they added to fat and oil containing foods?
In the reaction represented by the following equation:
CuO (s) + H2 (g) → Cu (s) + H2O (1)
(a) name the substance oxidised
(b) name the substance reduced
(c) name the oxidising agent
(d) name the reducing agent
In the context of redox reactions, the removal of hydrogen from a substance is known as:
(a) oxidation
(b) dehydration
(c) reduction
(d) dehydrogenation
Identify the substances that are oxidised and the substances that are reduced in the following reaction.
\[\ce{CuO_{(s)} + H2_{(g)} -> Cu_{(s)} + H2O_{(l)}}\]
How would you change a metal like Cu into its ions?
Identify from the reaction the reactants that undergo oxidation and reduction.
2Mg + O2 → 2MgO
In what respect does hydrogen differ from:
alkali metals
Compare hydrogen and halogens on the basis of:
reaction with oxygen
Describe briefly the ionic concept of oxidation and reduction. Give an equation to illustrate.
Complete and balance the following equation:
H2 + S → ___________
Complete and balance the following equation:
CuO +__________→ Cu +___________
Complete and balance the following equation:
\[\ce{K + H2O -> }\]________+ ________
State what is reducing agent. Give an example of oxidising agent in the gaseous, liquid, and solid form.
Oxidising agents are also called as ______ because they remove electrons form other substances.
The process of reduction involves ____________.
When Ag is exposed to air it gets a black coating of ____________.
During the reaction of some metals with dilute hydrochloric acid, following observations are made.
The temperature of the reaction mixture rises when aluminium (Al) is added.
Explain this observation giving suitable reason.
Mention some oxidation reactions that occur in daily life.
A reddish brown metal used in electrical wires when powdered and heated strongly turns black. When hydrogen gas is passed over this black substance, it regains its original colour. Based on this information answer the following questions:
- Name the metal and the black substance formed.
- Write balanced chemical equations for the two reactions involved in the above information
Metals are good ______.
