Question

Cobalt chloride is blue in dry state but in contact with moisture, it turns
A) Yellow
B) Pink
C) Green
D) Red

Answer 1

Cobalt chloride paper takes a look at is that the hygrometric takes a look at for transpiration. Dry Cobalt chloride is blue, whereas damp one's pink. A paper slip may be lordotic in three to five chlorides and dried. It seems blue. The slip is placed over the leaf surface and guarded from atmospherical wetness by a glass slide or clear tape. modification in color of the paper slip from blue to pink indicates transpiration.

Complete answer:
Cobalt chloride $CoC{l_2}$, may be a fascinating compound that changes colorize response to wetness. As wetness will increase, metal chloride changes color from sky blue to purple to pink. Such placing changes in color build metal chloride helpful as a wetness indicator in weather instruments.
As the humidity can increase, and water is absorbed by $CoC{l_2}$, the crystal structure rearranges itself to make space for water molecules. First, a pair of water molecules surround each element atom, forming the dihydrate, that's "chemistry speak" for "two water molecules." element chloride dihydrate is purple. The association reaction might even be pictured by the next chemical reaction
$CoC{l_2} + 2{H_2}O \to CoC{l_2}.2{H_2}O$
$CoC{l_2}.2{H_2}O + 4{H_2}O \to CoC{l_2}.6{H_2}O$
As the wetness will increase more, the crystal structure once more changes, now rearranging itself to let four a lot of water molecules in to surround every metal atom, forming the hexahydrate.
Chemical compounds of the part metal are used for thousands of years as coloring agents in paint, ink, ceramics and glass. metal glass, as an example, owes its engaging deep blue color to a compound of metal and gas, metal compound, $CoO$.

Hence the correct answer is option ‘B’.

Note: Chemists use the raised dot image before the ${H_2}O$ to point the quantity of water molecules that became incorporated into a compound at the atomic level. Heating the hydrous styles of metal chloride reverses the reactions higher than, returning metal chloride to the blue, water-free, or anhydrous, state. Water is "liberated" in these reactions, referred to as dehydration reactions.