) The types of bonds present in CuSO4.5H2O are only:

(IIT JEE 1983)

1) electrovalent and covalent 

2) electrovalent and coordinate covalent  

3) electrovalent, covalent  and coordinate covalent

4) covalent  and coordinate covalent

Logic & Solution:

* Structure of CuSO4.5H2O in the solid state is shown below. The Cu2+ ions are attracted towards SO4

2- ions not only by ionic interactions (electrovalent) but also by coordinate covalent bonds. The

Cu2+ ions form coordinate covalent bonds with water as well as sulfate ions.

There are covalent bonds in water and sulfate ions.

Conclusion:

The correct option is 3.

Note:

There is also hydrogen bonding between water and sulfate ions. Only four water molecules are forming dative bonds with Cu2+. The fifth molecules is involved in H-bonding.

Related questions

2) Which of the following contains both polar and non-polar bonds?

(IIT JEE 1997) 

1) NH4Cl 

2) HCN

3) H2O2

4) CH4

Logic & solution: 

1) In NH4Cl, the N-H bond is polar due to appreciable electronegativity difference between N (3.0) and H (2.1).

2) In HCN, the H-C and C-N bonds are polar due to electronegativity difference between C (2.5) and N (3.0) for H-C bond as well as between C (2.5) and  H (2.1) for C-N bond.

3) In H2O2, the O-H bond is polar due to electronegativity difference between O (3.5) and H (2.1). Whereas, O-O bond is non-polar.

4) In CH4, the C-H bonds are also polar.

Note: Even though, the C-H bonds have a little polarity, you might have seen that they are considered to be non-polar in the study of organic chemistry. It is a relative thing. They are less polar when compared to bonds formed by carbon with other atoms like: C-O, C-N, C-X etc. Hence C-H bonds are treated as non-polar.

But according to the tone of this question, C-H bonds are taken as polar since there is electronegativity difference. 

Conclusion:

Option '3' is correct.

3) The number and type of bonds between two carbon atoms in CaC2 are:

(IIT JEE 1996) 

1) one σ and one π bonds 

2) one σ and two π bonds

3) one σ and one and half  π bonds

4) one σ bond

Logic & solution: 

CaC2 can be divided into Ca2+ and C22- ions. The structure of C2

2- ion is shown below:

 

There is a triple bond between two carbons. Among three bonds, only one is sigma bond and the remaining two are pi bonds.

Conclusion:

Option '2' is correct.

4) Which one of the following molecule contains both ionic and covalent bonds?

(EAMCET 2002-E) 

1) CH2Cl2 

2) K2SO4 

3) BeCl2 

4) SO2

Logic & solution: 

 Only in K2SO4, there are ionic as well as covalent bonds. The K+ and SO42- ions are attracted by

electrostatic forces. Sulfur atom has covalent bonds in sulfate ion. 

 

Conclusion:

Option '2' is correct.

5) Element 'X' is strongly electropositive and element 'Y' is strongly electronegative. Both are univalent. The compound formed will be:

(IIT JEE 1980) 

1) X+Y-

2) Y+X-

3) X-Y

4) X→Y 

Logic & solution: 

 Strongly electropositive elements tend to lose electrons due to relatively low ionization potentials to form cations (like X+) and strongly electronegative elements tend to gain electrons to form anions (like Y-). Hence the bond formed between them is predominantly ionic in nature.

Conclusion:

Option '1' is correct.

6) The bond between two identical non metal atoms has a pair of electrons. The correct statement about this pair is:

(IIT JEE 1986) 

1) Unequally shared between the two.

2) Transferred fully from one atom to another

3) Has identical spins.

4) Equally shared between the atoms. 

Logic & solution: 

 Identical atoms possess same electronegativity values and hence share the electron pair equally by forming a non polar covalent bond.

Conclusion:

Option '4' is correct.

7) The bonds present in N2O5 are:

(IIT JEE 1986) 

1) only ionic

2) covalent and coordinate

3) only covalent

4) covalent and ionic 

Logic & solution: 

Since nitrogen and oxygen are non metals, the bonds between them are NOT ionic.

The structure of N2O5 is given below. There are both covalent and coordinate covalent bonds.

Conclusion:

Option '2' is correct.

 

1) The total number of electrons in one molecule of carbon dioxide is:

(IIT JEE 1979)

1) 22

2) 44

3) 66

4) 88

Logic:

Number of electrons in a molecule is equal to the sum of electrons in individual atoms in it.

# electrons in an atom is equal to its atomic number.

Solution:

In CO2, there are one carbon and two oxygen atoms and the number of electrons in them are:

In C ------> 6 electrons

In two O's -------> 2 x 8 electrons

Total in CO2 -------> 6 + (2 x 8) = 22 electrons.

Conclusion:

Correct option is '1'.

Related questions

2) The total number of electrons that take part in forming the bonds in N2 is: 

(IIT JEE 1980) 

1) 2

2) 4

3) 6

4) 8

 

Logic & Solution: 

In N2 molecule, there is a triple bond between two nitrogen atoms. Hence the number of electrons that participate in bond formation is 6. Each nitrogen atom contributes three electrons for bond formation.

Conclusion:

Correct option is '3'.

 

3) Pick out the isoelectronic structures from the following:

    I) CH3+    II) H3O+    III) NH3    IV) CH3

- 

(IIT JEE 1993) 

A) III & IV

B) I & II

C) I & III

D) II, III & IV

Logic & Solution: 

Species(sum of atomic numbers of each atom) - charge on the

speciesI) CH3

+ C + 3H - (+1) = 6 + 3(1) - 1 = 8II) H3O+ 3H + O - (+1) = 3(1) + 8 - 1 = 10III) NH3 N + 3H - (0) = 7 + 3(1) - 0 = 10IV) CH3

-  C + 3H - (-1) = 6 + 3(1) +1 = 10

H3O+, NH3 and CH3- are not only isoelectronic but are also iso-structural with pyramidal shape.

However CH3+ is trigonal planar with one empty orbital perpendicular to this plane.

Conclusion:

Correct option is 'D'.