Common body-centered cubic (bcc) metals do not include
a) chromiumb) titanium
c) aluminumd) tungsten

Titanium

Explanation:

BCC i.e. body-centered cubic is a type of non-primitive unit cell.

In bcc type crystal structure the atoms are arranged in the corners of the unit cell and also on the center of the body of that unit cell.

Among the given options Titanium is the only metal which does not form bcc type crystal structure.

Titanium forms hcp (hexagonal close packing ) type of crystal structure.

The coordination number of hcp is 12 and it is ABAB type lattice.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.