Formal Charges
Formal charges have an important role in organic chemistry since this concept helps us to know whether an atom in a molecule is neutral/bears a positive or negative charge. Even if some molecules are neutral, the atoms within that molecule need not be neutral atoms.
Polarity Of Water
In simple chemical terms, polarity refers to the separation of charges in a chemical species leading into formation of two polar ends which are positively charged end and negatively charged end. Polarity in any molecule occurs due to the differences in the electronegativities of the bonded atoms. Water, as we all know has two hydrogen atoms bonded to an oxygen atom. As oxygen is more electronegative than hydrogen thus, there exists polarity in the bonds which is why water is known as a polar solvent.
Valence Bond Theory Vbt
Valence bond theory (VBT) in simple terms explains how individual atomic orbitals with an unpaired electron each, come close to each other and overlap to form a molecular orbital giving a covalent bond. It gives a quantum mechanical approach to the formation of covalent bonds with the help of wavefunctions using attractive and repulsive energies when two atoms are brought from infinity to their internuclear distance.
![Q1. What mass of Li3PO4 is needed to prepare 500 ml. of a solution having a lithium ion concentration of
0.175 M?
A. 6.75 g
B. 10.1 g
C. 3.36 g
D. 19.3 g
Q2. A 47.27 g of Ca(OH)2 is dissolved in water to make 1.0 liters of solution. How many mL of this solution
must be diluted with water to make 1.0 L of 0.10 M Ca(OH)2?
A. 538.4 ml.
B. 658 ml.
Q3. Arrange the following in order of increasing first ionization energy
A. Rb<Ca<S<P
C. Rb< Ca<P<S
C. 156.7 ml.
Q4. Which pair of ions will form a precipitate (insoluble) when their solutions are mixed?
A. AP³+, NO,¹
B. K¹, S²
C. Na, PO¹
Q10. Which of the following is paired correctly?
A. H₂SO4 nonelectrolyte
C. BaCl₂ weak electrolyte
B. Rb<P<Ca<S
D. P<S<Ca<Rb
D. Ca²+, CO₂-²
Q5. Calculate the molar mass of the acid when 0.625 g sample of H₂X acid is completely neutralized with 45.2
ml. of 0.106 M NaOH.
A. 246.8 g/mol
B. 505.2 g/mol
C. 260.9 g/mol
D. 82.9 g/mol
Q6. Calculate of the light emitted by a H atom if an electron falls from n=7 to n=2 principal energy
level.
A. 3.97 × 10² nm
B. 101mm
C. 445nm
D. 2.16 x 10 m
Q7. The electron configuration for the iodine ion (1¹) is?
A. [Kr]5s²4d¹05p
B. [Xe]6s²
D. [Kr]4s3d¹04p
D. (6. 2, -3,-1/2)
C) 1s 2s 2p 3s 3p 4s²
Q8. The correct set of quantum numbers (n, 1, mi, m.) for an electron in a 6f orbital is?
A. (6, 2, 1, 1/2)
B. (6, 3, -2, -1/2)
C. (5, 2, 2, 1/2)
Q9. Which one of the following is the correct order for atomic radius? (largest to smallest)
A. K> F > P
B.K>P>F
C.F> P> K
A. 14, 2, 3
D. 3.34 mL
Q11. Which of the following frequencies corresponds to light with the shortest wavelength?
A. 3.00 × 10¹3 S-1
B. 4.12 x 10³ s
X
C. 8.50 × 1020 S-¹
Q12. What are the reacting ions in the following reaction?
Pb(NO3)2 + 2NaCl-PbCl₂ + 2NaNO3
B. Pb²+, C1¹
B. 7, 2, 3
B. HNO, weak electrolyte
D. HCI strong electrolyte
C. Pb². Na¹+
D. P> K>F
Cr₂O7² (aq) +1¹(aq) → Cr+³(aq) + 12 (aq)
1
C. 6, 2, 2
A. Na¹*, NO,¹-
D. Pb²+, NO3¹
Q13. When the following equation is balanced in acidic solution the coefficients for, H¹, Cr3, and Iz
respectively are?
D.9.12 × 1021 1
D. 14, 3, 2](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F73756e6a-601d-4e3a-a6d7-35b2b5f0e6cb%2Fbfd16042-e857-4617-9ccf-817065b06b85%2Ffxa3w5b_processed.jpeg&w=3840&q=75)
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