The B. Ca-F pair has the greatest electronegativity difference.
Electronegativities <em>increase from the lower left to the upper right</em> in the Periodic Table.
Ca is closest to the lower left, and F is in the upper right, so the Ca-F bond has the greatest electronegativity difference.
Answer:
Ammonia gas(an alkaline gas with characteristics of choking or irritating smell) is not liberated when 6mole of HCl is added to the solution instead of 6mole of NaOH, to test for the presence of ammonium ion in the solution
Explanation:
As expected, when testing for ammonium ion in a solution (precisely ammonium salt solution), Sodium Hydroxide (NaOH) is required as the test reagent.
When NaOH is added to the solution, A gas with characteristics of choking or irritating smell is liberated.
This gas turn red litmus paper blue.
This liberated gas is an alkaline gas, which is confirmed as an ammonia gas(NH3).
If HCl is added instead of NaOH, the ammonia gas will not be liberated, which indicates that the test reagent used is wrong.
Answer:
Np-237, Ar-40.
Explanation:
Alpha particle is positively charged particle having a mass of 4 unit. Hence,when alpha is removed from any isotope it produces a element having mass 4 units less than original isotope that was before emission. Americium 241 isotopes used in the smoke detector which emit an alpha particle to produce neptunium-237.
Potassium-40 emits positron which is having negative charge to lower one proton and increase one neutron number in the particle and in such way it will produce 
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<span>The number of moles in Al2O3 is .16575 moles</span>
First, we will get the number of moles:
one mole contains Avogadro's number of atoms. Therefore, to know the number of moles in <span>7.83 × 10^24 atoms, we will simply do cross multiplication as follows:
number of moles = (</span><span>7.83 × 10^24*1) / (6.022 * 10^23) = 13 moles
From the periodic table:
mass of one mole of helium = 4 grams
Therefore:
mass of 13 moles of helium = 13*4 = 52 grams</span>
