Advertisements
Advertisements
प्रश्न
Find the odd one out and give its explanation.
विकल्प
Na
K
Cu
Li
Advertisements
उत्तर
Cu
Explanation-
Copper (Cu) is a less reactive metal while others are highly reactive metals.
APPEARS IN
संबंधित प्रश्न
In the extraction of aluminium: Draw the diagram for the extraction of aluminium.
Which metal becomes black in the presence of hydrogen sulphide gas in air?
Give two uses of bronze.
Describe with one example, how moderately reactive metals (which are in the middle of reactivity series) are extracted.
Which metal is extracted from cinnabar ore?
Name one ore of mercury. Which mercury compound is present in this ore? Write its chemical formula.
Which of the following is an iron ore?
(a) cinnabar
(b) calamine
(c) haematite
(d) rock salt
The two metals which can be extracted just by heating their sulphides in air are:
(a) sodium and copper
(b) copper and aluminium
(c) potassium and zinc
(d) mercury and copper
Give reasons, why aluminum is used in:
painting electric and telegraphic poles
Aluminum is used in thermite welding:
what is ignition mixture?
Identify the process given in following passage and draw neat labelled diagram showing the process.
Electrolysis of molten mixture of alumina (melting point > 20000C) is done in a steel tank. The tank has a graphite lining on the inner side. This lining does the work of a cathode. A set of graphite rods dipped in the molten electrolyte works as anode. Cryolite (Na3AlF6) and fluorspar (CaF2) are added in the mixture to lower its melting point upto 10000C.
Give the chemical formula of :
Sodium aluminate
Name : The metal which is liquid at room temperature.
Calcium, copper, lead, aluminium, zinc, chromium, magnesium, iron.
Choose the major metals from the list given above to make the following alloys:
(a) Stainless steel
(b) brass
Name the following:
The process of heating an ore to a high temperature in the presence of air.
Correct the following statement :
Copper reacts with nitric acid to produce nitrogen dioxide.
Draw a well-labelled diagram of extraction of Aluminium. Write the anode reaction in electrolytic reduction of Alumina.
_______ is the least reactive metal.
In the electrolytic method, a layer of highly active metal is applied to a less active metal.
Answer the questions on the following passage.
The minerals from which the metal can be separated economically are called ores. Ores contain many types of impurities such as soil, sand and rocky substances along with metal compounds. These impurities are called gangue.
Metals can be extracted from their ores by means of various methods of separation. The process of extraction of metal in a pure state from the ores is also a part of metallurgy.
Ores are taken out from the mines and the gangue is usually separated from the ore at the site itself by various methods. Then the ores are carried out to the place where metals are produced. Here metals are extracted in pure form. Then metals are further purified by different methods of purification. This entire process is called metallurgy. Most metals being reactive do not occur in nature in the free state but are found in combined state as their salts such as oxides, carbonates, sulphides, and nitrates. however, the most unreactive metals that are not affected by air, water and other natural factors like silver, gold, platinum, generally occur in a free state. The compounds of metals that occur in nature along with the impurities are called minerals.
- What are ores?
- Which processes are involved in the branch of metallurgy? What is metallurgy?
- Which metals are found in a free state?
- In what forms are metals found in combined state?
- What is gangue?
