2[Au(CN)2]– + Zn \(\to\) [Zn(CN)4]2– + 2Au\(\downarrow\) is which of these
(A) Redox reaction
(B) Displacement reaction
(C) Combination reaction
(D) Decomposition reaction
The correct answer is A & B:
\[ 2[\text{Au(CN)}_2]^– + \text{Zn} \to [\text{Zn(CN)}_4]^{2–} + 2\text{Au} \]
This reaction involves the reduction of gold (\(Au\)) and the oxidation of zinc (\(Zn\)), making it a:
A block of mass 1 kg is pushed up a surface inclined to horizontal at an angle of \( 60^\circ \) by a force of 10 N parallel to the inclined surface. When the block is pushed up by 10 m along the inclined surface, the work done against frictional force is:
[Given: \( g = 10 \) m/s\( ^2 \), \( \mu_s = 0.1 \)]
A gas can be taken from A to B via two different processes ACB and ADB. When path ACB is used, \( 60 J \) of heat flows into the system and \( 30 J \) of work is done by the system. If path ADB is used, the work done by the system is \( 10 J \). The heat flow into the system in path ADB is:
Minerals are the naturally occurring, homogeneous inorganic solid substances. They are having a definite chemical composition and crystalline structure, hardness and color. For example, copper pyrite, calamine, etc.
Impurities in an ore are called gauge. The removal of a gauge from the ore is called concentration ore.
Several steps are involved in the extraction of pure metal from ores. Major steps are as follows –