Beyond the answers - interesting background to this quiz

A capital that is not the largest city

New Delhi has served as the seat of Indian government since the early twentieth century, when the British moved the capital from Calcutta. It forms part of the wider metropolis of Delhi, a city with layers of history stretching back centuries. Mumbai, often assumed to be the capital because of its size and financial weight, is actually the capital of Maharashtra state, not of the country.

Two capitals, one country

Bolivia is one of the few countries with more than one capital. Sucre remains the constitutional and judicial capital, while La Paz functions as the seat of government, hosting the presidency and congress. The arrangement dates back to political shifts in the late nineteenth century, and it still confuses travellers planning their itineraries.

Sulfuric acid, the workhorse of industry

Sulfuric acid, H2SO4, is one of the most produced industrial chemicals in the world, used in fertilisers, batteries and metal processing. Its formula reflects two hydrogen atoms, one sulfur atom and four oxygen atoms. The similar-looking HNO3 belongs to nitric acid, while HCl is hydrochloric acid, which is found in our stomachs.

Eight countries, one mountain range

The Alps stretch across eight countries: France, Monaco, Italy, Switzerland, Liechtenstein, Austria, Germany and Slovenia. That makes the range a rare example of a single landscape shared by so many borders, languages and cultures. Monaco and Liechtenstein, two of Europe's smallest states, both owe part of their identity to their alpine setting.

The detective who never said it

Arthur Conan Doyle introduced Sherlock Holmes in 1887 and eventually grew tired of his own creation, briefly killing him off before public demand brought him back. The famous phrase "Elementary, my dear Watson" does not appear in the stories in that exact form, though Holmes does use the word "elementary" on occasion. Agatha Christie and Edgar Allan Poe, the other names in the options, were both influential crime writers in their own right.