Liquid steel (300 metric tons) initially containing 0.03 mass% sulfur, is desulphurised with calcium (1000kg) according to the reaction, Ca + [S] = Ca S. The slag (1 metric ton) lying on top of metal contains (in mass%) 50% CaO, 25% SiO₂ and the rest is Al₂O₃. Only 10 mass% of the CaO injected reacts with the sulfur and the rest escapes as gas into the atmosphere.
What will be the final sulfur content, in mass% in liquid steel?

Identify the incorrect statement with reference to L.D. steel making

A. The temperature of L.D. furnace is maintained at around 1600°C

B. The basicity of slag is maintained at around unity

C. Dephosphorisation and decarburisation should proceed simultaneously

D. High silicon hot metal may lead to sloping

The oxidising power of a steel making slag is dependent on the concentration of

A. CaO, because Ca²⁺ ions are oxidising to the elements

B. CaO, because O^2- ions are oxidising to the elements

C. FeO, because Fe²⁺ ions are oxidising to the elements

D. FeO, because O^2- ions are oxidising to the elements

Inclusion free steel are known as

A. Plain carbon steel

B. Clean steel

C. Alloy steel

D. None of these

Determine the correctness or otherwise of the following Assertion(a) and Reason(r):
Assertion (a): Deoxidation and decarburisation of liquid steel are done by vacuum treatment process.
Reason (r): Decreased partial pressure of CO(g) promotes deoxidation and decarburisation.

A. a is false but r is true

B. a is true but r is false

C. a is true and r is also true, but r is not the reason for a

D. a is true and r is also true, and r is the reason for a