What is the coordination number for each of the following complexes or compounds? [co(nh3)4(h2o)2]3+ [cr(edta)]− [pt(nh3)4]2+ na[au(cl)2]?

[Co(NH₃)₄(H₂O)₂]³⁺: coordination number = 6.

[Cr(EDTA)]⁻: coordination number = 6.

[Pt(NH₃)₄]²⁺: coordination number = 4.

Na[Au(Cl)₂]: coordination number = 2.

Explanation:

In this complex, Co is bonded with 4 molecules of NH₃ (with 4 coordinate bonds, one bond for each molecule) and 2 molecules of H₂O (with 2 coordinate bonds, one bond for each molecule) forming the complex with 6 coordinate bonds.

∴ coordination number = 6.

In this complex, Cr is bonded with 1 molecules of EDTA (with 6 coordinate bonds, 4 O atoms and 2 N atoms in EDTA molecule).

∴ coordination number = 6.

In this complex, Pt is bonded with 4 molecules of NH₃ (with 4 coordinate bonds, one bond for each molecule).

coordination number = 4.

In this complex, Au is bonded with 2 atoms of Cl (with 2 coordinate bonds, one bond for each atom).

coordination number = 2.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

the answer is   c.) 1575 j.

explanation: