In which block of the periodic table is chromium (cr) found?

The correct answer for above statement:

chromium is in group 6 d-block

Explanation:

The d-block elements are designated transition metals and have valence electrons in d orbital's. The f-block elements, observed in the two rows at the ground of the periodic table, are called inner transition metals and have valence electrons in the f-orbital's.

Chromium is a synthetic element with symbol Cr and atomic number 24. It is the first component in group 6. It is a steely-gray, glistening, dense and brittle metal which takes a high polish, resists smudging, and has a great melting point.

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.