Answer:
Indicators show changes in the pH of a solution
Explanation:
A pH meter is an instrument that measures the hydrogen-ion activity in aqueous solutions, indicating the acidity or alkalinity of the solution expressed as pH .The pH meter measures the difference in electrical potential between a pH electrode and a reference electrode, hence the pH meter is sometimes referred to as a potentiometric pH meter. Potentiometric pH meters measure the voltage between two electrodes and display the result converted into the corresponding pH value. The instrument comprises of a simple electronic amplifier and a pair of electrodes, or alternatively a combination electrode, and some form of display calibrated in pH units. It usually has a glass electrode and a reference electrode, or a combination electrode. The electrodes, or probes, are inserted into the solution to be tested.
Organic indicators are chemical species that change their colour in response to changes in the pH of the solution. This implies that the anionic and protonated forms of the indicator possess different colours. Hence the colour changes in acidic, basic and neutral solutions. The images attached indicate the colour changes in phenolphthalein and methyl orange in acidic and basic media accordingly.
Answer: Option (C) is the correct answer.
Explanation:
Molecules in a liquid have less force of attraction as compared to solids. But liquid molecules have more force of attraction as compared to gases.
Since molecules of a gas are held together by weak Vander waal forces, therefore, they expand to fill the container whereas molecules in a liquid are not expanded in a container like gases because of more force of attraction within molecules of liquids as compared to gases.
Hence, a liquid can take the shape of container in which it is kept.
Thus, we can conclude that out of the given options, a liquid change to take the shape of its container but NOT expand to fill the container itself because the particles of a liquid are held together loosely enough to flow, but not so loose that they expand.
Answer:
Use the Bromotriflouride catalyst, BF₃
Explanation:
The BF₃ is most likely to yield less desired side products. The effect lies in the reaction mechanism.
BF₃ is a Lewis acid. Its role is to promote the ionization of the HF. This is achieved through the electrophilic mechanism. The reaction mechanism is as follows:
2 - methylpropene + H-F-BF₃ → H-F + H₃C + benzene
butylbenzene + F-BF₃ → tert-butylbenzene + H-F + BF₃ (regenerated catalyst)
The two forms of oxygen, O2 and O3 is "<span>They have different molecular structures and different properties."</span>
D. 2- youre adding two negative charges to a neutral element
