(Points: 10) For the following:
i) HClO4 > HBrO4 > HIO4
ii) NH3 > PH3 > AsH3 > SbH3
iii) HOClO3 > HOClO2 > HOClO > HOCl
iv) HBr>HCl>HF
The order of acidity is correct for which series?
1. ) all are correct
2. ) ii and iii
3. ) ii and iv
4. ) ii
5. ) i, iii, iv
To determine the correct answer, let's compare the acidity of each compound in the given series:
i) HClO4 > HBrO4 > HIO4: This series follows the trend of the halogens, with iodine (I) being the least acidic and chlorine (Cl) being the most acidic. Therefore, the order of acidity is correct.
ii) NH3 > PH3 > AsH3 > SbH3: This series follows the trend of the elements in the group, with nitrogen (N) being the least acidic and antimony (Sb) being the most acidic. Therefore, the order of acidity is correct.
iii) HOClO3 > HOClO2 > HOClO > HOCl: This series follows the trend of the electronegativity in the molecule. The oxygen (O) atoms in the series are successively more electronegative, making the molecule more acidic. Therefore, the order of acidity is correct.
iv) HBr > HCl > HF: This series follows the trend of electronegativity as well. Fluorine (F) is the most electronegative element, making HF the most acidic. Therefore, the order of acidity is correct.
From the analysis above, we can see that all series have the correct order of acidity. Therefore, the correct answer is option 1) all are correct.
To determine which series correctly orders the acidity, we need to understand the concept of acidity and the factors that influence it.
Acidity is the property of a substance to donate a proton (H+) in a chemical reaction. The stronger the acid, the more readily it donates a proton. Acidity is determined by the stability of the resulting conjugate base after the acid donates its proton.
In the given options, we have four series: i), ii), iii), and iv). Let's analyze each series:
i) HClO4 > HBrO4 > HIO4
This series involves oxyacids, where the central atom is bonded to oxygen and contains varying numbers of oxygen atoms. In general, the acidity of oxyacids increases with the electronegativity of the central atom and the number of oxygen atoms. Based on this trend, the order of acidity in this series is correct.
ii) NH3 > PH3 > AsH3 > SbH3
This series involves hydrides of elements from Group 15 of the periodic table. The acidity of these hydrides increases as the atomic size of the central atom increases. Based on this trend, the order of acidity in this series is correct.
iii) HOClO3 > HOClO2 > HOClO > HOCl
This series involves oxyacids of chlorine. In general, the acidity of oxyacids increases as the number of oxygen atoms attached to the central atom increases. Based on this trend, the order of acidity in this series is correct.
iv) HBr > HCl > HF
This series involves the hydrides of Group 17 elements. Acidity increases as we move across the halogens in Period 2 from left to right. Thus, the order of acidity in this series is correct.
Now analyzing all the series, we find that all of them correctly order the acidity. Therefore, the answer is option 1.) all are correct.