Answer:answers are in the explanation
Explanation:
(a). pH less than 7 between 1 - 3.5 are strong acid, and between 4.5-6.9 weak acid.
pH greater than 7; between 10-14 is a strong base, and between 7.1 - 9, it is weakly basic.
(b). Equation of reaction;
HBr + KOH ---------> KBr + H2O
One mole of HBr reacts with one mole of KOH to give one Mole of KBr and one mole of H2O
Calculating the mmol, we have;
mmol KOH = 28.0 ml × 0.50 M
mmol KOH= 14 mmol
mmol of HBr= 56 ml × 0.25M
mmol of HBr= 14 mmol
Both HBr and KOH are used up in the reaction, which leaves only the product,KBr and H2O.
The pH here is greater than 7
(C). [NH4^+] = 0.20 mol L^-1 × 50 ml. L^-1 ÷ 50 mL + 50mL
= 0.10 M
Ka=Kw/kb
10^-14/ 1.8× 10^-5
Ka= 5.56 ×10^-10
Therefore, ka= x^2 / 0.20
5.56e-10 = x^2/0.20
x= (0.20 × 5.56e-10)^2
x= 1.05 × 10^-5
pH = -log [H+]
pH= - log[1.05 × 10^-5]
pH = 4.98
Acidic(less than 7)
(c). 0.5 × 20/40
= 0.25 M
Ka= Kw/kb
kb= 10^-14/1.8× 10^-5
Kb = 5.56×10^-10
x= (5.56×10^-10 × 0.5)^2
x= 1.667×10^-5 M
pH will be basic
Answer:
The correct answer is - Positive charge occupies a very small volume in the atom.
Explanation:
Ernest Rutherford's experiments exhibited the presence of the nuclear core: a small region with the greater part of the mass of the atom and the positive charge.
Rutherford's gold foil analyze gave three conclusions:
- the particle is generally vacant space
- in it is a little, thick core or dense nucleus
- the core is positively charged.
The correct answer is acids and bases
the arrheius theory, introduced in 1887 by the Swedish scientist Svante Arrhenius<span>, that </span>acids<span> are substances that dissociate in water to yield electrically charged atoms or molecules, called </span>ions<span>, one of which is a </span>hydrogen ion<span> (H</span>+<span>), and that </span>basesionize in water to yield hydroxide ions (OH−). It is now known that the hydrogen ion cannot exist alone in water solution; rather, it exists in a combined state with a water molecule, as the hydronium ion (H3O+<span>). In practice the hydronium ion is still customarily referred to as the hydrogen ion.</span>
Answer: Cyclohexene
Explanation:
Cyclohexane belongs to the Alkenes family. Alkenes react in the cold with pure liquid bromine, or with a solution of bromine in an organic solvent like tetrachloromethane. The double bond breaks, and a bromine atom get attached to each carbon. The bromine loses its original red-brown color to give a colorless liquid. In the case of the reaction with ethene, 1,2-dibromoethane is formed. When bromine is added to cyclohexane in the dark room, there won't be any reaction. If the mixture is exposed to light however, free bromine radicals are generated. In this condition, polybrominated products can be produced as well.
Anthracene is a polycyclic aromatic hydrocarbon with chemical formula C₁₄H₁₀. The number of fused rings in Anthracene are three in number. This compound is colorful and is used in the formation of different dyes due to its property of deloclization of pi electrons. All the carbon atoms in Anthracene are sp² hybridized with a trigonal planar structure hence, the Anthracene is planar in nature.
Number of Sigma Bonds:
There are 26 sigma bonds (colored in Blue) in Anthracene among which 10 sigma bonds are between carbon and hydrogen atoms while the remaining are between the carbon atoms.
Number of Pi-Bonds:
There are 7 pi bonds in Anthracene (colored in red). All pi bonds are present between carbon and carbon atoms.
Number of Electrons in Sigma Bonds:
As one sigma bond is formed by 2 electrons hence, 26 sigma bonds will be formed by 52 electrons.
Number of Electrons in Pi Bonds:
As one pi bond is formed by the side wise overlap of two p orbitals hence one pi bond is formed by two electrons so, 7 pi bonds will be formed by 14 electrons.
