Advertisements
Advertisements
Question
How many carats is pure gold? Why is pure gold not suitable for making ornaments?
Solution
24-carat gold is pure gold. Pure gold is too soft and it is not possible to make ornaments from this soft gold. Thus, 24-carat gold is mixed with two parts of copper or silver for making jewellery. The gold used for jewellery is 22-carat gold.
APPEARS IN
RELATED QUESTIONS
Name the gas in air which tarnishes silver articles slowly.
Silver metal does not combine easily with oxygen but silver jewellery tarnishes after some time. How?
Define the term mineral.
How is sodium metal extracted? Explain with the help of equation of the reaction involved.
Answer the following questions based on the extraction of aluminium from alumina by Hall - Heroult’s Process :
Why is powdered coke sprinkled on top of the electrolyte?
Name the following:
The process in which an ore is heated in air so that oxygen gets added to it to form the oxides.
X is an element in the form of a powder. X burns in oxygen and the product is soluble in water. The solution is tested with litmus. Write down only the word which will correctly complete each of the following sentences:
(a) If X is a metal, then the litmus will turn ______.
(b) If X is a non-metal, then the litmus will turn ______.
(c) If X is a reactive metal, then ______ will be evolved, when X reacts with dilute sulphuric acid.
(d) If X is a non -metal, it will form _ oxide, which will form ______ solution with water.
(e) If X is a non -metal, it will not conduct electricity unless it is carbon in the form of ______.
In electrolytic reduction of alumina _______ is used as a cathode.
Iron is _______.
Explain the following reaction with the balanced equation.
Sodium aluminate reacts with water
