The tarnishing of silver spoon in presence of moisture is due to formation of
- \(AgO_2\)
- \(Ag_2S\)
- \(AgNO_3\)
- \(AgCl\)
The Correct Option is B
Solution and Explanation
Tarnishing of silver occurs due to its reaction with hydrogen sulfide (H₂S) gas present in moist air. This results in the formation of a black coating of silver sulfide (Ag₂S) on the surface of the silver object: \[ 2Ag + H_2S \rightarrow Ag_2S + H_2 \] This black layer of Ag₂S is what causes the silver spoon to appear tarnished.
The correct option is (B): \(Ag_2S\)
Top Questions on Corrosion
The figure shows a rod PQ, hinged at P, rotating counter-clockwise with a uniform angular speed of 15 rad/s. A block R translates along a slot cut out in rod PQ. At the instant shown the distance \( PR = 0.5 \, {m} \) and \( \theta = 60^\circ \). The relative velocity of R with respect to the rod PQ is 5 m/s at the instant shown. The relative acceleration of R with respect to the rod PQ is zero at the instant shown.
Which one of the following is the CORRECT magnitude of the absolute acceleration (in m/s\(^2\)) of block R?
Consider two blocks, P of mass 100 kg and Q of mass 150 kg, resting as shown in the figure. The angle \( \theta = 30^\circ \). The coefficient of friction between the two blocks is 0.2. Assume no friction exists at all other interfaces. The minimum force required to move the block P upward is \( W \). Which one of the following options is closest to the CORRECT magnitude of \( W \) (in N)?
A force of \( P = 100 \, {N} \) is applied at the ends of the pliers as shown in the figure. Neglecting friction, the force exerted by the upper jaw on the workpiece is ........... N (in integer).
- For a certain linear elastic isotropic material, the Young’s modulus is 140 GPa and the shear modulus is 50 GPa. The Poisson’s ratio for the material is ........... (rounded off to two decimal places).
Consider a beam with a square box cross-section as shown in the figure. The outer square has a length of 10 mm. The thickness of the section is 1 mm. The area moment of inertia about the x-axis is ........... mm\(^4\) (in integer).
Questions Asked in AP POLYCET exam
- If assumed mean of a data is 47.5, \( \sum f_i d_i = 435 \) and \( \sum f_i = 30 \), then mean of that data is:
- AP POLYCET - 2025
- Arithmetic Mean
- A prime number \( p \) divides \( a^2 \) where \( a \) is a positive integer, then
- AP POLYCET - 2025
- Prime and Composite Numbers
- A pair of linear equations \( a_1 x + b_1 y + c_1 = 0 \) and \( a_2 x + b_2 y + c_2 = 0 \) is such that \( \frac{a_1}{a_2} \neq \frac{b_1}{b_2} \), then they are:
- AP POLYCET - 2025
- Linear Equations
- Area of a sector of a circle with radius 4 cm and angle 30° is (use \( \pi = 3.14 \)):
- Two cars are seen from the top of a tower of height 75 m with angles of depression \(30^\circ\) and \(45^\circ\). If the cars are on opposite sides of the tower along the same line, the distance between them is:
- AP POLYCET - 2025
- Heights and Distances