The metal extracted by leaching with cyanide is

Which one of the following is a true peroxide?

What does the given structural formula represent?

Four thin rods of same mass $M$ and same length $l$ form a square as shown in the figure. The moment of inertia of this system about an axis passing through the centre $O$ and perpendicular to its plane is

Four successive members of the first series of the transition metals are listed below. For which one of them is the standard electrode potential $(E^o_{M^{2+}/M})$ value positive?

$A$ and $B$ are two radioactive substances whose half-lives are $1$ and $2$ years respectively. Initially, $10 \, g$ of $A$ and $1 \, g$ of $B$ are taken. The time (approximate) after which they will have the same quantity remaining is ........... $years$.