Answer: b [Reason:] The Pilling-Bedworth ratio is the ratio of the volume of the basic cell of a metal oxide to the volume of the basic cell of an equivalent or standard metal. It is used to find out the likeliness of the metal to corrode or resist it.

Answer: a [Reason:] The Faraday’s constant is used to determine the magnitude of electric charge per mole of electrons. It is denoted as F and is named after Michael Faraday. The accurate value of this constant is 96485.33289(59) C mol^-1.

Answer: a [Reason:] The Faraday’s constant is used to determine the magnitude of electric charge per mole of electrons. It is denoted by F = e N_A. Here, e is the charge of an electron and N_A is Avogadro’s constant.

Answer: c [Reason:] The free energy of formation of metal oxides is denoted by ΔG and is noted at 25^oC. This value is 1045 kJ mol^-1 for Cr₂O₃ and 1576 kJ mol^-1 for Al₂O₃.

Answer: b [Reason:] The Pilling-Bedworth ratio is the ratio of the volume of the basic cell of a metal oxide to the volume of the basic cell of an equivalent or standard metal. This ratio is 0.41, 0.79, 1.71, and 2.03 for K₂O, MgO, Cu₂O, and Cr₂O₃ in that order.

Answer: a [Reason:] Every material has a standard electrode potential that will change based on the purity of the metal. The potential under nonstandard condition is defined by V=V_o-RT/nF ln(M/(M+)).

Answer: b [Reason:] A region in the electrolyte where the metal ions are less in number is known as anodic. Such differences in concentration of metal ion may result in the formation of a galvanic cell known as concentration cell.

Answer: a [Reason:] A galvanic cell can be formed due to various residual stresses in a metal. The stressed region is more active and anodic in nature. These cells can be formed due to dislocation density in a cold worked metal or in a polycrystalline metal.

Answer: c [Reason:] When the potential of metal increases, its current density increases. However, after the critical value, it is lowered suddenly and remains constant for a while. This is known as passivation.

Answer: a [Reason:] Fracture is defined as the breaking of a material into multiple parts. The fracture stress is defined as meganewton per square meter or MN m^-2 and is denoted by σ_f.

Answer: b [Reason:] Fracture toughness is regarded as the rate of strain energy released. Its SI unit is joule per meter square (J m^-2) and is denoted as G_c.

Answer: d [Reason:] Calculations for shear strength of perfect crystal has been found to be similar to that of two adjacent planes. It was determined that the tensile strength necessary to rupture interatomic bonds of two adjacent atomic planes is of the order of Y/6.

Answer: d [Reason:] It was found that the tensile strength of two adjacent atomic planes was Y/6. However, brittle materials may break at a stress of the order of Y/1000. Here, Y is the Young’s modulus.

Answer: b [Reason:] In crystalline materials, fracture usually occurs after some deformation. In these materials, the fracture occurs normal to crystallographic planes called cleavage planes.

Answer: c [Reason:] Griffith suggested the norm for the formation and spreading of cracks in brittle materials. He found that the surface energy of the crack is 4 ϒ c. Here, ϒ is the surface energy per unit area of the material.

Answer: c [Reason:] When tensile stress is applied to a material, the maximum stress occurs at the tips. This maximum stress is denoted as σmax and is given by .

Answer: b [Reason:] The stress required to cause brittle fracture varies inversely as the square root of crack length. From observation, we understand that Griffith theory is applicable only to perfect brittle materials like glass.

Answer: c [Reason:] Pyrex is a borosilicate glass having a low thermal expansion. It consists of 80.5% SiO₂ along with B₂O₃ (11.9%), and small quantities of Na₂O, K₂O, CaO, and Al₂O₃. This glass is mainly used in laboratory equipment and kitchenware.

Answer: d [Reason:] Sodium carbonate is added to fused quartz glass to lower glass transition temperature. However, this results in water solubility. In order to prevent this, magnesia (MgO) and alumina (Al₂O₃) are added, which increases chemical durability of the glass.

Answer: d [Reason:] Fused quartz is a glass made of chemically-pure silica. It has tremendous resistance to thermal shock and has a melting temperature of about 1723^oC. However, it has a low thermal expansion and is generally hard.

Answer: a [Reason:] Soda lime glass is regarded as the most preferred form of glass due to its low cost and ease of use. Annealed glass can be used up to 860 F whereas tempered form may be usable up to 480 F. These glasses are used in ordinary windows and bottles.

Answer: c [Reason:] Kovar glass is a well-known type of sealing grade of borosilicate glass. These are used in glass-to-metal sealing applications.

Answer: b [Reason:] Optical grade is one brand of borosilicate glass illustrated by high light transmission (HLT). They also possess good corrosion resistance. The optical grade of glass is otherwise known as the crown.

Answer: b [Reason:] Lead glasses are known as lead-alkali glasses which contain lead as its primary constituent. They have high electrical resistivity and are moderately economical. These glasses are used in optical applications, neon-sign tubing, and electrical bulb stems.

Answer: a [Reason:] Fused silica is characterized as 100% silicon dioxide and is known as fused quartz in its naturally occurring state. It has a high level of transparency owing to its purity. This glass is heat resistant up to 1650 F in continuous service, and up to 4172 F in short-term service, making it the most heat-resistant glass.

Answer: a [Reason:] Ninety-six-percent silica glasses are similar to fused silica, but are easier to fabricate and have a higher coefficient of expansion. These can be used as heat shields in space vehicles and other chemical glassware. Aluminosilicate glasses can be used in high-temperature thermometers and combustion tubes.

Answer: c [Reason:] Aluminosilicate glasses are generally expensive and have more thermal shock resistance. Their maximum service temperature in the annealed state is 650^oC. The maximum service temperatures for soda lime and fused silica are 460^oC and 1200^oC correspondingly.

Answer: a [Reason:] Natural rubber is a common material consisting of isoprene combined with impurities and water. Natural rubber is also known as India rubber and belongs to natural polyisoprene chemical group.

Answer: a [Reason:] Styrene butadiene refers to a high abrasion resistant rubber composed of styrene and butadiene. These rubbers go by the common name of Buna S or SBR (styrene butadiene rubber). The percentage of elongation of SBR is 450-500%.

Answer: d [Reason:] Buna N is a synthetic rubber composed of acrylonitrile and butadiene. It is also commonly known as NBR, Krynac, or Europrene. This rubber is used in O-rings and hoses.

Answer: d [Reason:] Polysiloxane, otherwise known as silicone (SIL) is a rubber used for its temperature insulation properties. It has a 600% elongation and is most useful around a temperature range of -90oC to 250oC.

Answer: a [Reason:] Unvulcanized natural rubber is a tough and elastic material which softens of heating. It becomes tacky at 30^oC and hardens at around 5^oC. This rubber oxidizes to a sticky mass when out in the sun.

Answer: c [Reason:] Natural rubber is processed from a liquid known as rubber latex. It has high strength and possesses good tear and abrasion resistance. However, it is easily attacked by solvents and gasoline, and also possesses low hysteresis.

Answer: b [Reason:] Vulcanization is a process which increases the strength of natural rubber. It is carried out by heating a mixture of raw rubber and sulfur. The vulcanized rubber is commonly used in the manufacture of tires.

Answer: a [Reason:] Fillers can be classified as either reinforcing fillers or inactive fillers. Carbon black and synthetic white fibers based on silica and alumina are examples of reinforcing fillers. Talc, barium sulfate, chalk, and chinaclay are examples or inactive fillers.

Answer: b [Reason:] Buna S (SBR) rubbers differ and quality and grades with respect to the amount of styrene and butadiene. Low-temperature resistant rubber may only contain 9% styrene whereas 44% styrene has good flow characteristics. When the amount of styrene exceeds 50%, it is considered plastic.

Answer: c [Reason:] Polyacrylate elastomers, also known as acrylics, are composed of polymers of butyl or ethyl acrylate. These elastomers are used for special purposes with a low-volume usage, such as parts involving oil.

Answer: a [Reason:] Polybutadiene elastomers are known for their low-temperature performance. They have the lowest brittle or glass transition temperature after silicones. These elastomers possess excellent resilience and abrasion resistance.

Answer: c [Reason:] Chlorosulfonyl polyethylene is a special elastomer used in a combination with another elastomer or by itself. It is otherwise known as Hypalon or CSM. A polysulphide elastomer is otherwise known as Thiokol.

Answer: a [Reason:] Crystalline solids are classified as either metallic or non-metallic. Pb, along with Cu, Ag, Al, and Ni, has a face-centered cubic structure.

Answer: d [Reason:] Crystalline solids are classified as either metallic or non-metallic. W, Mo, and Cr are examples of the body-centered cubic structure of crystals. The HCP structure is found in Mg, Zn, Ti, Cd, Zr, and others.

Answer: c [Reason:] Materials in which the molecule is the basic structural solid and has an irregular structure is known as amorphous solid. Crystalline solids, on the other hand, usually are arranged in a regular manner.

Answer: d [Reason:] Similar to metallic crystals, a few non-metallic crystals also change form due to temperature and pressure differences. This process is termed as polymorphism. Iron changes from BCC at room temperature to FCC form at 906^oC.

Answer: b [Reason:] Similar to metallic crystals, a few non-metallic crystals also change form due to temperature and pressure differences. Tin crystallizes in a non-metallic diamond structure (gray tin) at low temperatures. At room temperature, it forms a metallic structure (white tin).

Answer: c [Reason:] Non-metallic crystals are less ductile and have low electrical conductivity. On the other hand, metallic crystals are differing since they are more ductile and have high electrical conductivity.

Answer: c [Reason:] Materials in which the molecule is the basic structural solid and has an irregular structure are known as amorphous solid. Most amorphous materials are polymers such as plastics and rubbers. The most common amorphous material is glass.

Answer: c [Reason:] Lattice is defined as the regular geometrical arrangement of points in a crystal space. Space or crystal lattice is a three-dimensional network of imaginary lines connecting the atoms.

Answer: d [Reason:] Lattice is defined as the regular geometrical arrangement of points in a crystal space. The unit cell is the smallest portion of the lattice, which when repeated in all directions gives rise to a lattice structure.

Answer: d [Reason:] There are fourteen ways in which points can be arranged in a space so that each has identical surroundings. These fourteen space lattices constitute the Bravais space lattices.

Answer: a [Reason:] If a unit cell chosen contains lattice points only at its corners, it is called a primitive or simple unit cell. It contains only one lattice point since each point at the eight corners is shared equally with adjacent unit cells.

Answer: d [Reason:] The crystal system is a format by which crystal structures are classified. Each crystal system is defined by the relationship between edge lengths a, b, and c. For monoclinic, orthorhombic, and triclinic systems, the axial relationship is given by a ≠ b ≠ c.

Answer: a [Reason:] The crystal system is a format by which crystal structures are classified. Each crystal system is defined by the relationship between edge lengths a, b, and c. For cubic and rhombohedral systems, the axial relationship is given by a = b = c.

Answer: b [Reason:] The crystal system is a system by which crystal structures are classified. Each crystal system is defined by the relationship between edge lengths a, b, and c and interaxial angles α, β, and ϒ. For hexagonal system, the interaxial angles are given by α = β = 90o ϒ = 120o.

Answer: d [Reason:] The crystal system is a system by which crystal structures are classified. Each crystal system is defined by the relationship between edge lengths a, b, and c and interaxial angles α, β, and ϒ. For the triclinic system, the interaxial angles are given by α ≠ β ≠ ϒ ≠ 90o.

Answer: d [Reason:] Atomic radius is defined as half the distance betwrrn the centers of two neighbouring atoms. The atomic radius of a simple cube and HCP is a/2 respectively, whereas it is a√2/4 and a√3/4 for FCC and BCC respectively.

Answer: a [Reason:] Coordination number is defined as the number of nearest neighboring atoms in crystals. The coordination number for simple cubic structure is 6, whereas it is 8 and 12 for BCC and FCC respectively.

Answer: b [Reason:] The density of packing in a crystal is determined using the atomic packing factor (APF). The APF of FCC and HCP structures is 0.74, and 0.54 for simple cubic structure, whereas it is 0.68 for BCC structure.