The percentage of silver in 'German silver' is:

Among statements $(a)-(d),$ the correct ones are
$(a)$ Limestone is decomposed to $CaO$ during the extraction of iron from its oxides.
$(b)$ In the extraction of silver,silver is extracted as an anionic complex.
$(c)$ Nickel is purified by Mond's process.
$(d)$ $Zr$ and $Ti$ are purified by Van Arkel method.

Railway wagon axles are made by heating rods of iron embedded in charcoal powder. The process is known as

Match List-$I$ with List-$II$ and select the correct code.

List-$I$	List-$II$
$I.$ Cyanide process	$a.$ Ultrapure $Ge$
$II.$ Froth floatation process	$b.$ Pine oil
$III.$ Electrolytic reduction	$c.$ Extraction of $Al$
$IV.$ Zone refining	$d.$ Extraction of $Au$

The major components in "Gun Metal" are

Match List-$I$ with List-$II$ and select the correct answer using the codes given below the list.

List-$I$	List-$II$
$1. Ti$	$A. \text{Bauxite}$
$2. Si$	$B. \text{Cerussite}$
$3. Al$	$C. \text{Van-Arkel method}$
$4. Pb$	$D. \text{Zone refining}$