Question

Which metal is mixed with gold to make an alloy ?

• A. Fe
• B. Cu
• C. Zn
• D. Ag

Hint:

The "karat" system measures gold purity. 24 karat is pure gold. 18 karat gold is 18/24 parts gold (75%) and 6/24 parts (25%) other metals like copper or silver.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Pure gold (24 karat) is a very soft metal, making it unsuitable for durable jewelry. To increase its hardness and change its color, it is mixed with other metals to form an alloy.

Step 2: Detailed Explanation:
The most common metals alloyed with gold for jewelry are copper, silver, nickel, and zinc.
\[\begin{array}{rl} \bullet & \text{Cu (Copper): Is a primary metal used to alloy with gold. It increases the hardness and gives the gold a reddish tint, creating "rose gold" in higher concentrations. } \\ \bullet & \text{Ag (Silver): Is also commonly used. It hardens the gold and gives it a whitish or greenish tint, leading to "white gold" or "green gold". } \\ \bullet & \text{Fe (Iron) and Zn (Zinc): While zinc is used in some gold alloys, iron is not typically used. } \\ \end{array}\] Both Copper (Cu) and Silver (Ag) are correct options, but Copper is the most common and essential alloying metal for standard yellow and rose gold. Given that Cu is an option, it is a very strong candidate.

Step 3: Final Answer:
Copper (Cu) is a common metal mixed with gold to make an alloy for jewelry.