Q1: Tin is not present as an alloying element in

ANS:D - white metal

White metal refers to a group of alloys that are known for their low melting points, high density, and white or silvery appearance. These alloys are commonly used in various applications where their low melting point, good casting properties, and resistance to corrosion are advantageous. White metal alloys typically consist of a combination of tin, lead, antimony, and sometimes other elements. Here are some key characteristics and aspects of white metal:

1. Composition: White metal alloys typically contain tin (Sn) as the primary component, along with lead (Pb), antimony (Sb), and sometimes small amounts of other elements such as copper (Cu) and bismuth (Bi). The exact composition of white metal alloys can vary depending on the desired properties and specific application.
2. Low Melting Point: One of the defining characteristics of white metal alloys is their low melting point, which typically ranges from around 150°C to 300°C, depending on the specific composition. This low melting point makes them suitable for casting into intricate shapes and for use in applications where soldering or brazing is required.
3. Density: White metal alloys have relatively high densities compared to other common metals. This high density makes them suitable for applications where weight is a consideration, such as in bearings and counterweights.
4. Casting Properties: White metal alloys have good casting properties, allowing them to be easily cast into complex shapes with fine details. This makes them suitable for use in various casting applications, including bearings, jewelry, figurines, and small mechanical components.
5. Corrosion Resistance: White metal alloys generally exhibit good resistance to corrosion, especially when properly maintained and protected from harsh environments. This corrosion resistance makes them suitable for use in marine environments and other applications where exposure to moisture or chemicals is a concern.
6. Applications: White metal alloys find applications in a wide range of industries, including automotive, aerospace, electronics, jewelry making, and industrial manufacturing. Common applications include bearings, bushings, gears, decorative items, soldering, and electrical contacts.