Corrosion and rancidity - class-IX
Which of the following methods is not used to coat metallic elements to prevent corrosion?
Rusting of iron is :
Rust is a\an ________ salt.
When the lead accumulator is charged, it acts as:
When lead storage battery is charged:
Which of the following is/are true regarding rancidity?
Number of Faradays involved in the net reaction of Lead accumulator is __________.
During the charging of lead accumulator battery voltage varies from:
Calcium hydroxide $\xrightarrow {\Delta}$ Calcium oxide + water. Identify the type of chemical reaction:
Balance the reaction of copper sulphide with dilute hydrochloric acid.
Correct balanced equation from the following reactions is:
Give a balanced equation for thermal dissociation of a solid [both containing the chloride ion].
The main cause of rancidity in foods is:
The term used to indicate the development of unpleasant smell and taste in fat and oil-containing foods due to aerial oxidation is:
The term 'rancidity' represents:
Glucose saline is used as:
Some oils and fats give a bad smell and taste because of _________ .
How many molecules of $CO _2$ are formed when one molecule of $C _6H _{12}O _6$ is oxidised in our body?
The moles of oxygen and carbondioxide involved in glycolysis are respectively:
Rancidity of fats can be prevented by antioxidants.
Solid calcium oxide reacts vigorously with water to form calcium hydroxide accompanied by liberation of heat. This process is called slaking of lime. Which among the following is (are) true about slaking of lime?
(i) It is an endothermic reaction
(ii) It is an exothermic reaction
(iii) The pH of the resulting solution will be more than seven
(iv) The pH of the resulting solution will be less than seven
Reactions in which energy is absorbed are known as........... reactions.
Rancidity can be prevented by -
Which step(s) in glycolysis require the input of energy?
In electrochemical passivity:
Any article of iron if left in open for some time, acquires a film of brownish substance (rust) having chemical formula:
Rusting of iron takes place only when both ...................... and ...................... are present.
Why corrosion is more seen in damp areas?
Corrosion occurs due to:
a) action of water on the metal.
b) action of air on the metal.
c) action of temperature on the metal.
Which of the following methods is suitable for preventing an iron frying pan from rusting?
Given,
$E _{Ag^{+}/Ag}^{\circ} = +0.80V, E _{Co^{2+}/Co}^{\circ} = -0.28 V, E _{Cu^{2+}/Cu}^{\circ} = +0.34 V, E _{Zn^{2+}/Zn}^{\circ} = -0.76V$,
Which metal will corrode to greater extent?
According to electrochemical theory of corrosion involves:
Which metal is usefull for protection of iron by corrosion?
Which of the following will be most easily corroded in moist air?
2 ml ethanoic acid was taken in test tubes - A, B and C. 2 ml, 4 ml and 8 ml of water was added to the test tubes A, B and C respectively. Which test tube will show clear solution?
Iron and rust are the same things.
In the atmosphere of industrial smog, copper corrodes to form:
Rusting of iron is catalysed by :
Iron is not protected from rusting by:
Iron articles rust readily whereas steel which is also mainly made of iron will not undergo corrosion.
The technique of protecting a metal from corrosion by connecting it to a second metal (that is more easily oxidized) is called:
Which metals does not corrode easily?
If edible oil is allowed to stand for a long time in an iron or tin container, the oil becomes rancid.
A shiny brown-coloured element 'X' on heating in air becomes black in colour. Name the element 'X'?
Assertion: Rusting of Fe is quicker in saline water than in ordinary water.
Reason: Presence of $Na^+$ and $Cl^-$ ions increase the conductance of the saline water.
No rusting takes place in absence of moisture.
An oxide of iron from the following is:
Iron can be prevented from rusting by:
Which of the following statements is/are incorrect ?
In the atmosphere of industrial smog, copper corrodes to form:
The presence of electrolytes ................ the rate of corrosion.
Aluminium is more reactive than iron. But aluminium is less easily corroded than iron because:
Corrosion of metals can be prevented when contact between metal and ________ is cut off.
Rusting of iron involves:
Which of the following statement is not true?
Lead pipes are readily corroded by:
When a corroded metal object is rubbed by a sand paper then:
If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of:
According to the electrochemical concept, corrosion occurs at :
Mark the correct statement:
a) Damp air alone supplies both things needed for corrosion.
b) Ordinary water supplies both air and water for corrosion.
c) Moist air can't provide both things.
What is corrosion?
If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of:
Which of the following metals has been used for building boats because it has resistance to corrosion by sea water?
In the rusting of iron, iron has been:
Iron nails rust fast when used for fixing plates or strips of aluminium on a building. Similarly, a water pipe made of iron corrodes faster when connected to a pipe of copper. This happens because of the?
The presence of $CO _2$ in the atmosphere results in:
The tarnishing of silver ornaments in atmosphere is due to:
Which metal is protected by a layer of its own oxide?
Zinc corrodes in ____________________.
Rusting of iron is catalysed by which of the following: