Test: Metals - SSC CGL MCQ

Silver is regarded as the best conductor of heat among the metals. This property makes silver highly valuable in various industrial applications such as electronics and thermal coatings. The high thermal conductivity of silver enables efficient heat transfer, making it a crucial material in the production of heat-sensitive components and devices.

Sodium and potassium stand out from the other mentioned metals due to their softness, which allows them to be cut with a knife. This characteristic is a result of their relatively low hardness compared to typical metals. Their softness makes them easier to manipulate and shape for various applications, especially in industries where their unique properties are advantageous.

Caesium and gallium transition from solid to liquid states above 30°C. This property of being liquid at relatively low temperatures distinguishes them from most metals, which are solid at room temperature. Caesium and gallium's low melting points make them unique elements with interesting applications in various fields, such as research and specialized industries.

Storing alkali metals such as lithium, sodium, potassium, rubidium, and caesium under kerosene or liquid paraffin is done to protect them from air. When exposed to air, alkali metals can react with the oxygen and moisture in the air, leading to unwanted chemical reactions. This protective measure helps maintain the purity and properties of the alkali metals.

Metallic sodium is primarily produced by the electrolysis of a molten mixture of 40% sodium chloride and 60% calcium chloride in a Down's cell. This process involves passing an electric current through the molten mixture to separate sodium metal from the chloride compounds. The extracted metallic sodium is then collected for various industrial applications.

Potassium superoxide (KO2) is primarily used in applications where oxygen production is needed. It is commonly employed in space capsules, submarines, and breathing masks to generate oxygen and remove carbon dioxide and carbon monoxide from the air. This property makes it crucial for sustaining life in enclosed environments where oxygen supply is limited.

Magnesium hydroxide, known as Milk of Magnesia, is commonly used as an antacid to neutralize excess stomach acid and provide relief from indigestion and heartburn. It works by reducing the acidity in the stomach, thereby alleviating symptoms of acid-related conditions.

Calcium sulphate, known as gypsum, partially loses its water of crystallization when heated to 120°C, transforming into plaster of Paris. Plaster of Paris is a versatile material used in various applications like building plaster, medical casts, and dental molds due to its ability to harden when mixed with water.

Barium sulphate (BaSO4) is primarily used as a white pigment, either alone or in combination with zinc sulphide to form lithopone. This compound is valued for its high opacity and brightness, making it a popular choice in various industries, including paints, coatings, and plastics.

Borax (Na₂B₄O₇·10H₂O) is primarily used in borax bead tests for qualitative analysis. This test is a method used in chemistry to detect the presence of certain metals in a given substance by observing the color of the borax bead when heated with the substance. It is a common procedure in qualitative inorganic analysis to identify the presence of various metal ions.

Aluminium (Al) is known for its versatile uses in making utensils, frames, and bodies of automobiles and aircraft. Due to its lightweight nature and corrosion resistance, aluminium is a popular choice in various industries for manufacturing a wide range of products.

Titanium chloride (TiCl₄) is primarily used in making screens. This compound finds application in various industries for producing screens with specific properties suited for different purposes, such as filtration, separation, or protection.

Metals exhibit an electropositive behavior by losing electrons to form positive ions. This characteristic is fundamental to understanding the reactivity and chemical properties of metals in various reactions. When metals lose electrons, they achieve a more stable electron configuration, leading to the formation of positively charged ions. This process is essential in the formation of metal compounds and their interactions with other elements.

A sodium chloride/calcium chloride blend is preferred over pure sodium chloride for de-icing roads because it helps lower the environmental impact. These blends are less corrosive to infrastructure and vegetation compared to pure sodium chloride, making them a more environmentally friendly choice for de-icing purposes.

Calcium carbide (CaC2) is extensively used in industrial processes for the preparation of acetylene gas. Acetylene has various applications, including as a precursor in the synthesis of many organic compounds and as a fuel in welding and cutting processes due to its high flame temperature.