Question

Which of the following are sulphate ores?
A.Cinnabar
B.Gypsum
C.Galena
D.Iron pyrite

Answer 1

For finding out answers to these types of questions, you need to remember the formula of ores. Now a question arises what ores are? Ores are the natural rock that contains the minerals, minerals can be of any elements so names were given to ores with respect to the mineral they have or on the basis of elements they consist of.

Complete step-by-step answer: We get an idea what ores are, these are rocks which contain minerals. Now it depends on whether ore contains one mineral or more than one. There are many processes related to the property of minerals as well as their compounds by which they got separated. We read it in metallurgy chapter where from a number of ore we can easily separate the minerals and then further metals from it.
If we take the first option, cinnabar is mercury ore when you hear of mercury, keep in mind that most mercury compounds are toxic. So, yes cinnabar is a toxic mercury sulfide ore having formula (HgS) if we talk about its physical appearance it is of red color and used mostly for jewellery carving. As cinnabar is a sulfide ore and not a sulphate ore thus this is not the correct option.
Next we have gypsum, if you have read about POP (plaster of Paris) it is having molecular formula as $CaS{O_4}.\dfrac{1}{2}{H_2}O$ while gypsum is a calcium sulphate ore having formula $CaS{O_4}.2{H_2}O$ it contains two water molecules. So, as we need sulphate ore this can be our answer let’s check for further ores.
We have a third option as Galena is a lead sulphide ore which is a very glittery silver physical appearance. It crystallizes in a cubic crystal system and often shows octahedral forms. Its uses are for production of lead and like mercury it is also toxic if inhaled but the ore is handled safely.
Last we have, Iron pyrite as its name suggests that it is an iron ore having formula $Fe{S_2}$ its physical appearance is just like gold hence its other name is also “Fool’s gold” . Pyrite is metallic lustre and pale brass yellow colour.
Among all the option that we have discussed our correct option is-

Hence, Option B is correct.

Note: In the above ores that we have given some of them are sulfide and some are sulphate. Now, don’t get confused with both, sulfide ion is having formula ${S^{2 - }}$ ore which forms compounds with this are come under sulfide ore while sulphate ion is different it has formula $SO_4^{2 - }$ so the metal which forms compound with this are called to be sulphate ores. There are also sulphide ores present.