Chemical Industry Multiple Choice Questions on “Inorganic Chemical – Propellants”.
1. Nitromethane is which type of propellants?
c) Solid propellants
d) Liquid propellants
Clarification: Liquid propellants are two types- homogeneous and compound. Nitromethane and ethyl nitrate comes under the categories of homogeneous liquid propellants and liquid ammonia, ammonium nitrate comes in compound propellants.
2. What is ‘hydrazine’?
a) Hypergolic material
b) Non-hypergolic material
c) Principal oxidizers
d) Principal fuels
Clarification: In liquid propellants, kerosene (JP-4), hydrazine,liquid H2 are used as principal fuels while H2O2, HNO3, N2O4, liquid O2 and liquid F2 are used as principal oxidizers.
3. Which one is not an ideal performance criterion for propellants?
b) Low toxicity
c) Low density
d) High heat of reaction
Clarification: Ideal performance criteria for propellants are- high heat of reaction, low molecular weight combustion products, high density, non-corrosive, low toxicity, readily ignitable and low cost.
4. What is the major disadvantage associated with solid propellants compared to liquid propellants?
a) Temperature sensitivity
b) High pressure
c) Low pressure
d) Insensitive to friction
Clarification: The burning rate in solid propellants is dependent upon the prior storage temperature. This temperature sensitivity is a major disadvantage of solid propellants when compared with liquid propellants.
5. Ammonia-sodium hypochlorite process is associated with which type of propellants production?
a) Boron-hydrogen compounds
Clarification: Hydrazine is produced by this ammonia-sodium hypochlorite process where anhydrous NH3 is injected into aqueous chloramine solution to give molar excess of NH3.
6. Which process is used in sodium hypochlorite process to produce final product of anhydrous hydrazine?
a) Azeotropic distillation
c) Continuous distillation
d) Batch distillation
Clarification: In ammonia- sodium hypochlorite process anhydrous hydrazine is produced by an azeotropic distillation process using aniline which takes the water overhead as an aniline water azeotrope.
7. How methyl borate is prepared?
a) CH3OH + B2
b) CH3OH + B3H3O6
c) CH3OH + B3H3
d) CH3OH + B2O4
Clarification: Methyl borate is prepared by the reaction of methanol with metaboric acid. Sodium hydride is prepared as dispersion and added to a jacket reactor along with methyl borate and resulting sodium borohydride reaction.
8. In which type of burning process of solid propellants usually a solid grain is used?
a) Progressive burn
b) Digressive burn
c) Neutral burn
d) Natural burn
Clarification: In digressive burn of solid propellants usually a solid grain in the shape of a cylinder or sphere is used. In progressive burn usually a grain with multiple perforations or a star cut in the centre providing a lot of surface area is used.
9. Polysulfide is which types of propellants?
a) Composite propellants
c) Single base propellants
d) Double base propellants
Clarification: Composite propellants are solid rocket fuels, consisting of oxygen donating inorganic salts and a binder made of plastics. The polymeric binders include polysulfide’s, polybutadiene etc.
10. What is HTPB?
a) An oxidizer
b) A metallic fuel
c) Curing agents
Clarification: Basically HTPB(Hydroxy-terminated polybutadiene) is one of a binder. Binders are composition that hold together a charge of finely divided particles and increased mechanical strength of the resulting propellant hrain.