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Answer:
Explanation:
1)A - Aluminum metal
B - Aluminum oxide
C - Sodium hydroxide
Explanation:
Metal A belongs to 3 period and group 13 so it is Aluminum
Generally Water does not react with aluminium due to the layer of oxide on it.
But when When steam is passed over red hot aluminium, hydrogen is produced.
2 Al + 3 H2O → Al2O3 + 3 H2↑
(steam) (aluminium oxide)
It reacts with strong caustic alkali like sodium hydroxide forming Sodium metal aluminate.
2 Al + 2 NaOH +2 H2O → 2 NaAlO2 + 3 H2↑
(Sodium meta aluminate)
so
A - Aluminum metal
B - Aluminum oxide
C - Sodium hydroxide
2)Nitric acid (dilute or conc) renders aluminium passive. ... Because when aluminium comes into contact with nitric acid, an impervious layer ofaluminium oxide is formed. This layer of aluminium oxide will prevent the nitric acid from coming into contact with the inner aluminium metal.
3)a)You should note that each atom in the H-Br molecule has a full valence shell. Both the hydrogen and the bromine can count the two electrons in the bond as its own because the electrons are shared between both atoms. Hydrogen needs only two electrons to fill its valence, which it gets through the covalent bond.
b)The objective is to identify the hazardous properties of chemicals which may constitute a risk during normal handling or use, risks to health, property or the environment.
The user of the chemicals is also to be introduced to the hazards they present and given the basic information, in a suitable manner, such as using a properly made label.
In this document one component chemical is called a substance, a mixture composed of two or more substances is called a preparation.
The hazards of preparations can be assessed using the information on hazards of their component substances. (See example 2.)
For classification purposes the degree of hazard depends not only on the properties of a dangerous substance but also on the level of exposure. This refers to the concentration of hazardous components in the mixtures. In order to assess a preparation it is essential to know also the quantities of its hazardous minor components.
The EU classification and labelling system used here as an example can be applied to dangerous substances and preparations. However, this system should not be applied to medical or veterinary products, cosmetics, munitions or explosives, pesticides specified elsewhere, waste and foodstuffs or animal feedstuffs in the finished stage. These have their own specifications and requirements for labelling.
c)Elements in the same period have the same number of electron shells; moving across a period (so progressing from group to group), elements gain electrons and protons and become less metallic. This arrangement reflects the periodic recurrence of similar properties as the atomic number increases.
Explanation: